docs(bazzite): warn on the user-facing page that 0.26.0-1 cannot stream the Desktop

packaging/bazzite/README.md already carries this, but that file ships inside the repo — the page a
field user actually lands on is /docs/bazzite, and it said only that the virtual output 'needs no
config'. On 0.26.0-1 that reads as a lie: the image granted the host CAP_SYS_NICE, so KWin cannot
read the /proc/<pid>/exe it identifies clients by, the shipped .desktop can never match, and every
Desktop session dies with 'KWin does not expose zkde_screencast_unstable_v1 to this client' —
looking exactly like the setup on that page was done wrong.

Says so, and gives the only repair that works: a merged sysext's /usr is read-only, so it is the
next image (punktfunk-sysext update), not a setcap -r. Notes Gaming Mode is unaffected.

Written as a bolded blockquote, the admonition style every other page uses. NOT a {{< callout >}}
shortcode — this site is Fumadocs/MDX, not Hugo, and no shortcode exists anywhere in it. Verified by
running the real build (bun install + vite build) rather than assuming: it completes clean, and the
backticked /proc/<pid>/exe follows the same pattern as the existing <pkg>/<token> in arch.md and
automation.md, which MDX leaves alone inside inline code.

.gitea/workflows/arch.yml

@@ -48,7 +48,26 @@ on:
     # `punktfunk-canary` pacman repo as X.Y.Z-0.<run#> (sorts below the eventual X.Y.Z-1),
     # tags to `punktfunk` — separate repos, so neither channel can shadow the other.
     tags: ['v*']
+  # REBUILDING A PUBLISHED RELEASE, because on a rolling distro the ground moves under one.
+  # Arch went FFmpeg 8 -> 9 (every libav soname +1) four minutes before v0.25.0 was tagged, so
+  # the release's punktfunk-host was linked in a builder image that still had 8 and shipped
+  # `libavcodec.so=62-64`. No up-to-date Arch box can satisfy that — and pacman prepares the
+  # whole transaction at once, so it did not merely block our package, it blocked those users'
+  # entire `pacman -Syu`. The repair is a rebuild of the SAME upstream version at a HIGHER
+  # pkgrel; nothing else reaches a box that already has the broken build recorded in its db.
+  # The workflow file at the tag can never carry inputs added after it was tagged, so dispatch
+  # this from `main`: it checks the tag's SOURCE out, publishes to the STABLE repo, and
+  # replaces the release-page assets. Same lever for any future "the distro moved" rebuild.
   workflow_dispatch:
+    inputs:
+      release_tag:
+        description: 'Rebuild this published release (e.g. v0.25.0) into the stable `punktfunk` repo. Empty = ordinary canary build of the dispatched ref.'
+        required: false
+        default: ''
+      pkgrel:
+        description: 'pkgrel for that rebuild — MUST be above the published one (2, 3, …); a same-pkgrel republish is invisible to pacman. Ignored without release_tag.'
+        required: false
+        default: '2'
 
 env:
   REGISTRY: git.unom.io
@@ -94,7 +113,52 @@ jobs:
           }
           bun --version
 
+      # THE BUILDER'S FFmpeg IS PART OF THE PACKAGE CONTRACT, not merely a build detail.
+      # packaging/arch/PKGBUILD binds punktfunk-host to the exact libav sonames it linked
+      # (`libavcodec.so=63-64` …), so a builder one FFmpeg major behind Arch emits a package
+      # that NOBODY can install — and takes the user's whole `pacman -Syu` down with it, since
+      # pacman prepares the transaction as a unit. That is exactly how v0.25.0 shipped: PR #108
+      # re-keyed this image for FFmpeg 9, the release tag fired four minutes later, and the job
+      # still got the FFmpeg-8 `:latest`. The image is a cache and is allowed to lag — but never
+      # on this one axis. So heal it in-job and shout, instead of building a dead package.
+      # (Runs BEFORE checkout: a stale image should be repaired before anything depends on it.)
+      - name: FFmpeg soname parity with today's Arch (heals a stale builder image)
+        run: |
+          export LC_ALL=C   # `Provides` is a localized field name
+          # Piped (never a TTY here) pacman prints each field on ONE line, unwrapped.
+          sonames() { sed -n 's/^Provides *: *//p' | tr ' ' '\n' | grep -E '^lib(av|sw)[a-z]*\.so=' | sort | tr '\n' ' '; }
+          # A SEPARATE --dbpath: this refreshes only a throwaway view of the repos, so the
+          # container's own db never enters the partial-upgrade state a bare `pacman -Sy` leaves.
+          mkdir -p /tmp/pf-archsync
+          if ! pacman -Sy --dbpath /tmp/pf-archsync --logfile /dev/null >/dev/null 2>&1; then
+            echo "::warning::could not refresh the Arch db — skipping the FFmpeg parity check"
+            exit 0
+          fi
+          HAVE="$(pacman -Qi ffmpeg | sonames)"
+          WANT="$(pacman -Si --dbpath /tmp/pf-archsync ffmpeg | sonames)"
+          echo "builder ffmpeg $(pacman -Q ffmpeg | cut -d' ' -f2): $HAVE"
+          echo "arch    ffmpeg $(pacman -Si --dbpath /tmp/pf-archsync ffmpeg | sed -n 's/^Version *: *//p'): $WANT"
+          if [ "$HAVE" = "$WANT" ]; then
+            echo "OK: the builder links the FFmpeg every up-to-date Arch box already has"
+            exit 0
+          fi
+          echo "::warning::arch-ci is stale ACROSS AN FFMPEG SONAME BUMP — upgrading it for this run."
+          echo "::warning::Bump the 'refreshed:' date in ci/arch-ci.Dockerfile so the IMAGE carries it."
+          pacman -Syu --noconfirm || true
+          HAVE="$(pacman -Qi ffmpeg | sonames)"
+          if [ "$HAVE" != "$WANT" ]; then
+            echo "::error::builder still links $HAVE while Arch ships $WANT."
+            echo "::error::Building on would publish a package no Arch box can install."
+            exit 1
+          fi
+          echo "healed: builder now links $HAVE"
+
       - uses: actions/checkout@v4
+        with:
+          # A dispatched release rebuild takes its WORKFLOW from the ref you dispatch (the only
+          # way it can carry inputs the tag predates) and its SOURCE from the tag. Empty string
+          # = checkout's own default, i.e. the triggering ref, for every other trigger.
+          ref: ${{ github.event.inputs.release_tag }}
 
       # Cache cargo's git dir too, not just the registry: the workspace includes
       # clients/windows, whose windows-reactor/windows deps are git-pinned — cargo must CLONE
@@ -127,12 +191,30 @@ jobs:
         # Keep the leading `0.` — it is what sorts a canary BELOW the eventual `X.Y.Z-1` stable
         # release. (A pkgrel is digits+dots only, so `0.` is the only prefix available; raising
         # it to `1.` would sort canaries ABOVE the release and is not an option.)
+        env:
+          RELEASE_TAG: ${{ github.event.inputs.release_tag }}
+          REBUILD_PKGREL: ${{ github.event.inputs.pkgrel }}
         run: |
           eval "$(bash scripts/ci/pf-version.sh)"   # -> PF_BASE (one minor ahead of latest stable)
-          case "$GITHUB_REF" in
-            refs/tags/v*) V="${GITHUB_REF_NAME#v}"; R="1";                       REPO=punktfunk ;;
-            *)            V="$PF_BASE";  R="0.$(printf '%08d' "$GITHUB_RUN_NUMBER")";  REPO=punktfunk-canary ;;
-          esac
+          if [ -n "${RELEASE_TAG:-}" ]; then
+            # Dispatched rebuild of a published release (see the workflow_dispatch note at the
+            # top): same upstream version, higher pkgrel, straight into the stable repo.
+            # ⚠ Keep that pkgrel SINGLE-DIGIT. Gitea's Arch registry picks the version its .db
+            # advertises by STRING order (the same trap the canary zero-padding below exists for),
+            # so "0.25.0-10" sorts BELOW "0.25.0-2" and the rebuild would never be advertised.
+            V="${RELEASE_TAG#v}"
+            R="${REBUILD_PKGREL:-2}"
+            REPO=punktfunk
+            case "$R" in
+              ''|*[!0-9.]*) echo "::error::pkgrel '$R' is not digits+dots"; exit 1 ;;
+              1) echo "::error::pkgrel 1 is the published build — a rebuild MUST go up (2, 3, …)"; exit 1 ;;
+            esac
+          else
+            case "$GITHUB_REF" in
+              refs/tags/v*) V="${GITHUB_REF_NAME#v}"; R="1";                       REPO=punktfunk ;;
+              *)            V="$PF_BASE";  R="0.$(printf '%08d' "$GITHUB_RUN_NUMBER")";  REPO=punktfunk-canary ;;
+            esac
+          fi
           echo "PF_PKGVER=$V" >> "$GITHUB_ENV"
           echo "PF_PKGREL=$R" >> "$GITHUB_ENV"
           echo "REPO=$REPO" >> "$GITHUB_ENV"
@@ -235,6 +317,63 @@ jobs:
             rm -rf dist-gamescope   # never cache a failed build (an empty path is not saved)
           fi
 
+      # THE GATE THIS PIPELINE WAS MISSING. The soname assert above proves the libav dep is
+      # VERSIONED; it cannot prove the version is one that EXISTS. v0.25.0 passed it and still
+      # shipped `libavcodec.so=62-64` to a world that had moved to 63 — every affected user got
+      # "unable to satisfy dependency … required by punktfunk-host", and because pacman prepares
+      # one transaction, their whole system upgrade stopped there. So ask the only question that
+      # matters before publishing: would a real, up-to-date Arch box install this?
+      #
+      # An empty --dbpath is what makes the answer honest. It means "nothing is installed", so
+      # pacman must satisfy every dependency FROM THE REPOS exactly as a user's box does. Checking
+      # against the builder's own installed set instead would let a stale ffmpeg satisfy the stale
+      # bound and hide the break completely — the very illusion that shipped v0.25.0. `--print`
+      # resolves and prints; it downloads nothing and installs nothing. Verified against the real
+      # broken artifact on an ffmpeg-9 box: it reproduces the user-visible failure verbatim.
+      - name: Assert every package installs on an up-to-date Arch box
+        run: |
+          export LC_ALL=C
+          mkdir -p /tmp/pf-instcheck
+          if ! pacman -Sy --dbpath /tmp/pf-instcheck --logfile /dev/null >/dev/null 2>&1; then
+            echo "::error::could not sync the Arch db — cannot prove these packages install"
+            exit 1
+          fi
+          check() {   # check FILE -> 0 installable, 1 not (reason on stdout)
+            pacman -U --print --noconfirm --dbpath /tmp/pf-instcheck --logfile /dev/null "$1" 2>&1
+          }
+          ls dist/*.pkg.tar.zst >/dev/null 2>&1 || { echo "::error::nothing in dist/ to check"; exit 1; }
+          rc=0
+          for pkg in dist/*.pkg.tar.zst; do
+            if out="$(check "$pkg")"; then
+              echo "OK  $(basename "$pkg")  ($(echo "$out" | wc -l) targets resolve)"
+            else
+              rc=1
+              echo "::error::$(basename "$pkg") CANNOT be installed on an up-to-date Arch box:"
+              echo "$out" | sed 's/^/    /'
+            fi
+          done
+          # gamescope stays best-effort, exactly as its build step is: a companion that cannot
+          # install is dropped from the upload with a warning, never a reason to withhold the
+          # packages this workflow exists to publish. (It is also the one package that can be
+          # restored from a cache older than the current Arch snapshot.)
+          for pkg in dist-gamescope/*.pkg.tar.zst; do
+            [ -e "$pkg" ] || continue
+            if out="$(check "$pkg")"; then
+              echo "OK  $(basename "$pkg")  ($(echo "$out" | wc -l) targets resolve)"
+            else
+              echo "::warning::$(basename "$pkg") is not installable on current Arch — NOT publishing it"
+              echo "$out" | sed 's/^/    /'
+              rm -f "$pkg"
+            fi
+          done
+          if [ "$rc" != 0 ]; then
+            echo "::error::refusing to publish: pacman would reject this on a current box, and a"
+            echo "::error::rejected dependency blocks the user's ENTIRE upgrade, not just punktfunk."
+            echo "::error::Usual cause: the arch-ci builder image lags Arch across a soname bump —"
+            echo "::error::bump 'refreshed:' in ci/arch-ci.Dockerfile, let docker.yml republish it, re-run."
+            exit 1
+          fi
+
       # NOTE deliberately NO sysext image is built or published here: a prebuilt HOST binary on
       # SteamOS breaks on the next A/B soname bump (and /var — where sysexts live — is
       # per-partition-set), which is the standing packaging verdict behind the on-device
@@ -262,14 +401,48 @@ jobs:
           done
           echo "published to $OWNER/arch/$REPO"
 
-      # On a real release, also attach the packages to the unified Gitea Release.
-      - name: Attach packages to the Gitea release (stable tags only)
-        if: startsWith(gitea.ref, 'refs/tags/v')
+      # On a real release, also attach the packages to the unified Gitea Release. A dispatched
+      # rebuild attaches to that SAME release object: the release page is a distribution surface
+      # too, and leaving the superseded .pkg.tar.zst sitting on it is one click away from handing
+      # someone the exact break the rebuild exists to fix.
+      - name: Attach packages to the Gitea release (stable tags + release rebuilds)
+        if: startsWith(gitea.ref, 'refs/tags/v') || github.event.inputs.release_tag != ''
         env:
           GITEA_TOKEN: ${{ secrets.REGISTRY_TOKEN }}
+          RELEASE_TAG: ${{ github.event.inputs.release_tag }}
         run: |
           . scripts/ci/gitea-release.sh
-          RID=$(ensure_release "$GITHUB_REF_NAME" "$GITHUB_REF_NAME" auto)
+          TAG="${RELEASE_TAG:-$GITHUB_REF_NAME}"
+          RID=$(ensure_release "$TAG" "$TAG" auto)
           for pkg in dist/*.pkg.tar.zst; do
             upsert_asset "$RID" "$pkg"
           done
+          # A rebuild bumps pkgrel, so its FILENAMES differ from the ones already attached, and
+          # upsert_asset only replaces by name — the superseded set would survive untouched.
+          # Drop every pacman asset (and .sha256 sidecar) this upload did not just write.
+          #
+          # ⚠⚠ THIS MUST LIVE IN THE WORKFLOW, NOT IN scripts/ci/gitea-release.sh. The sourced
+          # script comes from the CHECKED-OUT TREE, which on a release rebuild is the OLD TAG —
+          # so it can only ever offer the helpers that existed when that tag was cut. A helper
+          # added for this feature is therefore guaranteed ABSENT in the one code path that
+          # calls it: the first attempt failed with `prune_release_assets: command not found`
+          # after publishing perfectly. Only the workflow file itself is taken from the ref you
+          # dispatch. Same reason a packaging fix made after a tag does NOT reach a rebuild of
+          # that tag — the PKGBUILD is the tag's too.
+          if [ -n "${RELEASE_TAG:-}" ]; then
+            KEEP="$(cd dist && printf '%s ' *.pkg.tar.zst)"
+            # An UNMATCHED glob would come through literally and match nothing in the keep set —
+            # i.e. "delete every pacman asset on the release". Skip entirely instead.
+            case "$KEEP" in *'*'*) KEEP="" ;; esac
+            API="$GITHUB_SERVER_URL/api/v1/repos/$GITHUB_REPOSITORY"
+            if [ -n "$KEEP" ]; then
+              curl -fsS "$API/releases/$RID/assets" -H "Authorization: token $GITEA_TOKEN" \
+                | python3 -c "import json,sys;k=set(sys.argv[1].split());k|={n+'.sha256' for n in k};print('\n'.join('%s %s'%(a['id'],a['name']) for a in json.load(sys.stdin) if a.get('name','').endswith(('.pkg.tar.zst','.pkg.tar.zst.sha256')) and a['name'] not in k))" "$KEEP" \
+                | while read -r id name; do
+                    [ -n "$id" ] || continue
+                    echo "dropping superseded release asset: $name"
+                    curl -fsS -o /dev/null -X DELETE "$API/releases/$RID/assets/$id" \
+                      -H "Authorization: token $GITEA_TOKEN" || true
+                  done
+            fi
+          fi

.gitea/workflows/deb.yml

@@ -320,6 +320,46 @@ jobs:
         run: |
           VERSION="$VERSION" BUNDLE_FFMPEG=1 bash packaging/debian/build-deb.sh
 
+      # punktfunk-gamescope for apt. Same reasoning as the RPM leg in rpm.yml: without a packaged
+      # build, a Debian/Ubuntu box has no route to the patched gamescope except compiling it, and a
+      # stock gamescope streams SDR, cursorless, and tells every game its display is 60 Hz.
+      #
+      # CACHED on packaging/gamescope/** alone — it depends on nothing else in this repo, so a
+      # normal push restores a binary instead of spending ~10 minutes on someone else's tree.
+      - uses: actions/cache@v4
+        id: gamescope
+        with:
+          path: gs-cache
+          key: punktfunk-gamescope-noble-${{ hashFiles('packaging/gamescope/**') }}
+
+      - name: Build the patched gamescope
+        if: steps.gamescope.outputs.cache-hit != 'true'
+        # Best-effort, exactly like rpm.yml: the host packages above are the primary delivery and
+        # work without this binary, so a hiccup building an unrelated tree must not fail the job.
+        # `build-dep gamescope` resolves the distro's much older packaged version, so it can come up
+        # short — that is what the `|| true`s absorb, and the marker check downstream is what makes
+        # a half-built result impossible to ship.
+        run: |
+          set -x
+          apt-get update
+          apt-get install -y --no-install-recommends meson ninja-build glslc git || true
+          apt-get build-dep -y gamescope || true
+          if bash packaging/gamescope/build-punktfunk-gamescope.sh \
+               --destdir "$PWD/gs-stage" --prefix /usr --jobs "$(nproc)"; then
+            install -Dm0755 gs-stage/usr/bin/punktfunk-gamescope gs-cache/punktfunk-gamescope
+          else
+            echo "::warning::punktfunk-gamescope failed to build on noble — no .deb this run (gamescope sessions stay SDR)"
+          fi
+
+      - name: Build punktfunk-gamescope .deb
+        # Picked up by the publish loop below, which globs dist/*.deb.
+        run: |
+          if [ -x gs-cache/punktfunk-gamescope ] && gs-cache/punktfunk-gamescope --version >/dev/null 2>&1; then
+            bash packaging/debian/build-gamescope-deb.sh --binary gs-cache/punktfunk-gamescope
+          else
+            echo "::warning::no usable punktfunk-gamescope — skipping its .deb"
+          fi
+
       - name: Publish to the Gitea apt registry
         env:
           TOKEN: ${{ secrets.REGISTRY_TOKEN }}

.gitea/workflows/rpm.yml

@@ -213,6 +213,40 @@ jobs:
             echo "::warning::punktfunk-gamescope failed to build for f${{ matrix.fedver }} — the sysext ships without it (gamescope sessions stay SDR)"
           fi
 
+      # The same binary, as an ordinary RPM. The sysext below is the Atomic/Bazzite delivery; this
+      # is the one a traditional Fedora-family box (Nobara, plain Fedora) can actually install —
+      # until it existed those users had no packaged route to the patched build at all, and a stock
+      # gamescope tells every game its display is 60 Hz whatever the client negotiated.
+      #
+      # Same best-effort rule as the build above: no binary, no package, and the host stays on its
+      # existing SDR/host-composited path. The spec re-checks the +pfhdr marker itself.
+      - name: Package punktfunk-gamescope as an RPM
+        run: |
+          if [ -x gs-cache/punktfunk-gamescope ] && gs-cache/punktfunk-gamescope --version >/dev/null 2>&1; then
+            bash packaging/gamescope/build-gamescope-rpm.sh \
+              --binary gs-cache/punktfunk-gamescope \
+              --release "$PF_RELEASE"
+          else
+            echo "::warning::no usable punktfunk-gamescope for f${{ matrix.fedver }} — skipping its RPM"
+          fi
+
+      - name: Publish punktfunk-gamescope to the Gitea RPM registry
+        env:
+          TOKEN: ${{ secrets.REGISTRY_TOKEN }}
+        run: |
+          shopt -s nullglob
+          for rpm in dist/punktfunk-gamescope-*.rpm; do
+            case "$rpm" in *debuginfo*|*debugsource*) continue;; esac
+            NAME=$(rpm -qp --qf '%{NAME}' "$rpm" 2>/dev/null)
+            VR=$(rpm -qp --qf '%{VERSION}-%{RELEASE}' "$rpm" 2>/dev/null)
+            ARCH=$(rpm -qp --qf '%{ARCH}' "$rpm" 2>/dev/null)
+            echo "uploading $rpm"
+            curl -fsS -o /dev/null --user "enricobuehler:$TOKEN" -X DELETE \
+              "https://$REGISTRY/api/packages/$OWNER/rpm/$GROUP/package/$NAME/$VR/$ARCH" || true
+            curl -fsS --user "enricobuehler:$TOKEN" --upload-file "$rpm" \
+              "https://$REGISTRY/api/packages/$OWNER/rpm/$GROUP/upload"
+          done
+
       # The no-layering Bazzite path: wrap the just-built host + web RPMs into a systemd-sysext
       # image and publish it to the per-Fedora-major feed (punktfunk-sysext/f43[-canary], …) that
       # `punktfunk-sysext install|update` reads. Same RPMs, same channels — just no rpm-ostree.

CHANGELOG.md

@@ -12,6 +12,426 @@ with the version table of the release you are moving to, then read **Breaking ch
 
 ---
 
+## v0.26.0
+
+47 commits since v0.25.0.
+
+### Versions
+
+| | v0.25.0 | v0.26.0 | Notes |
+|---|---|---|---|
+| Wire protocol | 2 | **2** | unchanged |
+| C ABI | 17 | **17** | unchanged — no symbol added, removed or changed |
+| Workspace crate dirs | 26 | **26** | unchanged (40 workspace members) |
+| Virtual-display driver protocol | 6 | **6** | unchanged (minimum accepted still 3) |
+| Windows virtual-gamepad channel | 3 | **3** | unchanged |
+| Plugin index schema | 1 | **1** | unchanged |
+| `api/openapi.json` | 0.24.0 | **0.25.0** | tracks API edits, lags one release by convention |
+| gamescope patch level (`+pfhdrN`) | 2 | **4** | 3 patches → 6; `pkgrel` 1 → 2 |
+| `@punktfunk/host` (SDK) | 0.1.2 | **0.1.4** | |
+| `@punktfunk/plugin-kit` | 0.3.2 | **0.4.0** | the `plugin` launch kind |
+
+`crates/pf-driver-proto` is byte-for-byte identical to v0.25.0 and to v0.24.0 — if you ship the
+virtual-display driver or the gamepad channel, the last two releases have not touched you.
+
+### ⚠ Breaking changes
+
+**None.** This is a fixes release. Every embedder, packager and plugin that works against v0.25.0
+works against v0.26.0 unchanged. Two behaviour changes are worth knowing about anyway, because both
+make a client advertise *less* than it used to — see **Capability advertisement** below.
+
+### Capability advertisement
+
+- **`VIDEO_CAP_444` is now probed, not asserted.** It rode the "Full chroma" setting alone. That was
+  safe while a software HEVC decoder sat underneath it; M8 removed one (there is no permissively
+  licensed HEVC CPU decoder, so `software_decodable_codecs()` is `H264|AV1`). The host grants 4:4:4
+  on HEVC **only** and answers the resolved chroma in the `Welcome` *before* the client builds a
+  decoder — so on a device with no 4:4:4 decode the toggle did not cost crispness, it cost the whole
+  codec: the Vulkan rung refuses the shape at construction, VAAPI refuses it too, there is no CPU
+  rung, and the session reconnects on H.264. No AMD silicon has HEVC 4:4:4 decode, so every Steam
+  Deck with that switch on lost HEVC. Per-profile and default-off, which is why it read as
+  intermittent.
+
+  Now gated on `hevc_444_hardware_decodable`, which asks the driver through the same code the rung
+  uses at construction (`VkH265Decoder::probe_stream_support`). **Both depths are required**, not
+  either: with HDR the host may resolve 4:4:4 10-bit, and a device offering `YUV444_8` but not
+  `YUV444_10` lands in the same hole. Answering from the Vulkan rung alone is exact rather than
+  approximate — it is the only rung in this build that implements 4:4:4 at all
+  (`pf_vaadec::profile_for` errors on `chroma_format_idc 3`, pf-dxvadec refuses anything but 4:2:0,
+  the CPU rung is 8-bit 4:2:0).
+
+  ⚠ Deliberately **not** extended to `VIDEO_CAP_10BIT`/HDR: all three rungs implement 10-bit 4:2:0,
+  so a Vulkan-only probe there would withdraw HDR from boxes whose VAAPI/DXVA rung decodes it
+  perfectly — a regression against a case never observed.
+
+  The bit arithmetic moved into `video::video_caps_for` so the part that was wrong is testable
+  without a GPU, a host or a `Hello`; the test is verified non-vacuous against the planted defect.
+
+### Host and client environment variables
+
+Four new, one clarified. Verified new by `git grep` at the v0.25.0 tag, not assumed —
+`PUNKTFUNK_JUMBO`, `PUNKTFUNK_WIRE_MTU`, `PUNKTFUNK_STREAMED_AU`, `PUNKTFUNK_LIBRARY_ART_ROOTS`,
+`PUNKTFUNK_RECOVER_SESSION_CMD`, `PUNKTFUNK_GAMESCOPE_SDR_NITS`, `PUNKTFUNK_MAX_FPS` and
+`PUNKTFUNK_ON_CONNECT_CMD` all already existed.
+
+- **`PUNKTFUNK_OVERLAY_MASK`** *(new, client)* — controls the Steam-overlay input mask below.
+- **`PUNKTFUNK_PYROWAVE_CHUNK_KIB`** *(new)* and **`PUNKTFUNK_PYROWAVE_STREAMED_AU`** *(new)* —
+  PyroWave AU chunking and the streamed-AU path.
+- **`PYROWAVE_QUEUE_PRIORITY`** *(existed, but was inert on Linux — see below)* — grammar: unset →
+  realtime, ASCII-lowercased, `off` alone disables, `high` asks for HIGH only, junk falls back to
+  the ladder rather than to off. ⚠ **One env var must not mean two things on two platforms**, so
+  the Rust grammar is unit-tested against the C patch's, including where both are deliberately
+  un-clever (neither trims).
+- **`PUNKTFUNK_GAMESCOPE_REFRESH_RATES=60,90,120`** *(new)* — widens the set a gamescope session
+  offers in Steam's in-session display settings. The rate the session actually runs at is always
+  included, so it can only add options; junk entries are skipped rather than failing the host.
+  Requires gamescope patch level 3+.
+- **`PUNKTFUNK_COMPOSITOR`** *(behaviour clarified, not changed)* — documented as "which backend to
+  drive", it also silently discarded `game_session=dedicated`: `resolve_compositor` gated the
+  dedicated route on `!overridden` and logged nothing either way. The pin still wins — it is the
+  operator's explicit knob — but it now says so and names itself. Two further holes closed with it:
+  the pin put its backend into `available()` unconditionally *and* skipped `apply_session_env`'s
+  `XDG_CURRENT_DESKTOP` scrub, so `pick_compositor` could never return `None` — the one call site of
+  `try_recover_session()`, which left `PUNKTFUNK_RECOVER_SESSION_CMD` unreachable behind that arm.
+  Liveness is now read on both paths. `needs_live_session()` exempts gamescope, which stands up its
+  own session, so pinning it on a headless box stays supported.
+
+### Client settings keys
+
+All additive; an older client ignores what it does not know, and a newer value can never trap an
+older client.
+
+- **`gamepad_ui_mode`** — `"connected"` (default, and exactly what the previous lone Bool meant) or
+  `"always"`. Splits *whether* the controller UI is offered from *when* it appears.
+  `GamepadUIEnvironment.isActive` takes the mode with **no default argument** on purpose: a call
+  site that forgot it would silently strand everyone who chose Always. An unrecognized value waits
+  for a controller.
+- **`ui_palette`** gains `oled` at **index 1**, directly after the brand default — keeping
+  `PALETTES[0]` the unknown-id fallback and the dark-to-pale cycling order intact. Hand-mirrored in
+  three languages (`pf-console-ui`'s `library.rs`, `GamepadPalette.swift`, `GamepadPalette.kt`); each
+  port carries an `oled_is_actually_black` test that measures the claim (mean cell luminance 0.019
+  against Violet's 0.254) rather than restating the table.
+- **`library-hidden.json`** — per-title hide list, mirroring how `library-scanners.json` holds
+  disabled sources. Deliberately **not** stored on the entry: a scanner's and a plugin's titles are
+  rebuilt from scratch on every scan and reconcile, so a flag written onto one would be erased
+  minutes later. Applied in `all_games`, the single funnel every play surface already goes through
+  (client grid, native clients, the GameStream app list, launch resolution).
+
+### gamescope patches
+
+Three → six, and the marker patch moves last so the banner is stamped after the capabilities it
+advertises.
+
+- **0003 — headless: advertise the virtual display's mode and refresh rates.** `CHeadlessConnector`
+  returned empty spans from `GetModes()` and `GetValidDynamicRefreshRates()` and reported
+  `GAMESCOPE_SCREEN_TYPE_INTERNAL`, so `update_mode_atoms` **deleted** the mode-list atom and
+  wlserver fell through to a one-entry refresh list built from `g_nOutputRefresh` — which, with
+  `--nested-refresh` absent, is `Init()`'s 60 Hz default. That is why a 1920x1080@120 client saw
+  "gamescope only shows 60hz" and Overwatch capped itself to 60 while the stream ran at 120. Now
+  populates both from the resolved mode, reports `EXTERNAL`, and adds `--custom-refresh-rates`.
+  gamescope-session-plus has probed for that flag for years; upstream never had it, so the
+  `CUSTOM_REFRESH_RATES` env it plumbs was a no-op everywhere.
+- **0004 — pipewire: optionally composite the external overlay into the capture stream.** That layer
+  is mangoapp. `paint_pipewire` has never referenced it on any version. Behind
+  `--pipewire-composite-external-overlay`, off by default.
+- **0006 — never destroy the Vulkan device or output.** `g_device` (`CVulkanDevice`) and `g_output`
+  (`VulkanOutput_t`) were plain globals, so glibc ran their destructors from `__run_exit_handlers`
+  once `main()` returned — calling back into an ICD that had already been torn down and unloaded.
+  Faulting address equalling the instruction pointer is the signature. Reproducible with
+  `gamescope --backend headless -W 1280 -H 720 -r 60 --xwayland-count 1 -- true` (exit 139, every
+  time). Both globals get storage constructed exactly as before but never destroyed; pinning only
+  the device relocated the fault into `~VulkanOutput_t`, hence a shared `CNoDestroy<T>`.
+
+  ⚠ **`+pfhdrN` deliberately does not move for 0006.** The marker is a capability tier the host
+  probes via `gamescope_patch_level()` *before* it spawns; this patch adds no capability, so bumping
+  it would advertise a tier that does not exist. Ships as a `pkgrel` bump instead.
+
+⚠ gamescope CI legs are best-effort — a broken patch is a **missing package**, not a red run.
+
+### Virtual-display handle ownership (Windows)
+
+The control-device sharing contract was "bare `HANDLE` copies, never closed for the process
+lifetime": retired handles were kept alive because pinger/linger threads and capture closures held
+raw copies whose soundness depended on no-close. An open control handle is exactly what vetoes the
+PnP disable — and can wedge the `pnputil` restart — that wake-from-sleep recovery leans on, so every
+post-wake adapter reload came back REFUSED. `reset-pf-vdisplay.ps1` stops the whole host service
+precisely to get those handles closed; the in-process recovery could not.
+
+Ownership is now `Arc` all the way out: `ensure_device` / `device_handle` / `control_device_handle`
+hand out `Arc<OwnedHandle>` clones, every consumer holds its clone across its IOCTLs (ending the
+`isize` smuggling — `Arc<OwnedHandle>` is `Send + Sync`), and retiring drops only the manager's
+reference. `DeviceSlot::retired` is gone.
+
+⚠ **Nothing may store a bare control `HANDLE` again.** The whole fix is that the handle closes when
+the last in-flight user drains.
+
+### Presenter — points are not pixels
+
+`SDL_GetDesktopDisplayMode` reports a mode in **screen coordinates** and hands the pixels-per-point
+ratio back separately as `pixel_density`; `m.w`/`m.h` were read raw. KDE advertises a 2560x1600 panel
+at 150 % as 1707x1067 points with a density of ~1.4997, `render_scale::apply` even-floors both odd
+axes, and 1706x1066 went on the wire. Multiplying by the density recovers 2560x1600 to the pixel.
+
+⚠ Inert on X11 and Windows: SDL never sets a density there and `SDL_video.c` normalizes the unset
+0.0 to 1.0. **This bug needed a compositor doing fractional scaling.**
+
+Second, independent defect: the SDL window was created without `HIGH_PIXEL_DENSITY`, so the Wayland
+surface stayed at buffer scale 1 and the swapchain was built at 1707x1067 for KWin to upscale. That
+one also silently shrank "Match window", which asks the host for `size_in_pixels()`.
+
+### Apple audio session
+
+`micEnabled` and `echoCancel` both default to `true`, so the **default** iOS session is
+`.playAndRecord` — and that branch set `.defaultToSpeaker`. That option is an output **override**,
+not a preference, and it outranks an A2DP route. ⚠ **Wired headphones beat it, Bluetooth does not**,
+so testing with a cable returns the wrong answer — which is what the comment sitting on it asserted.
+
+Now solved against the route actually given: after activation, if the current output is
+`.builtInReceiver`, override to speaker; anything external (Bluetooth, wired, CarPlay, AirPlay) is
+left strictly alone. The override is a property of the current route — iOS drops it on every route
+change, which is what lets a newly-connected headset win — so it is re-applied per route via an
+observer, registered only for `.playAndRecord`, removed in `stop()` before deactivate, `deinit` as
+backstop. Without it, dropping Bluetooth mid-stream lands on the earpiece.
+
+⚠ Deliberately **not** adding `.allowBluetooth`: it would make a headset's mic usable but drag the
+whole route onto HFP/SCO and collapse game audio to narrowband.
+
+### Audio jitter policy
+
+`JitterPolicy` (`punktfunk-core/src/audio.rs`, used by Linux/Windows/Android) and its mirror in
+Swift `AudioRing`. The policy learned exclusively from audible failures on both sides: growth needed
+**three** audible underruns; the A/V sync loop re-tested a shallower ring every five quiet seconds
+and paid an audible starvation event every time it was wrong, forever; and a grown target was never
+re-banked (growth raises a threshold — only a re-prime deepens the ring), so a bunching link rode
+the knife edge with the "grown" target sitting inert.
+
+Three mechanisms: **near-miss** (a read served with less than one protocol frame left over is the
+same evidence as an underrun, heard by no one — grows one step per window, *before* the click);
+**shrink probes** (every shrink armed for 5 s, undone on the spot if answered by an underrun or
+near-miss, with a doubling backoff 60 s → 8 min on a failed sync-driven shrink; a surviving probe
+resets it); **hollow re-prime** (an underrun while the depth *average* runs more than a step below
+target re-primes immediately — the average, not the instant, separates a hollow ring from one late
+packet, and it is seeded on prime so a fresh ring is never spuriously hollow).
+
+Measured on a ten-minute simulation of the Wi-Fi power-save pattern (25 ms gaps / 300 ms, −50 ppm
+skew): **~2000 audible events → 9.**
+
+### Plugins, SDK and the runner
+
+- **`category` never shipped.** The console correctly keeps `category: "library"` plugins out of the
+  nav; the host reported no category for them at all. `defineLibraryPlugin` sets it and
+  `sdk/src/ui.ts` forwards it — what shipped did not: `@punktfunk/host` was bumped to 0.1.2 on
+  2026-07-20 and `category` landed 2026-08-05 without a bump, so the registry's 0.1.2 is the
+  pre-category build. ⚠ **Inert until published.** `serveUi` now reads its own directory entry back
+  and warns once when a requested category did not land.
+- **Local art sync failed on a `file://` disagreement.** `local_art_bytes` decodes a `file://` value
+  before testing containment; `validate_art_paths` handed the raw value to `Path::new`. Same defect
+  produced both the unreachable settings and `sync (startup) failed: HostRequestError`.
+- **The runner now carries SDK updates.** The copy each installed plugin runs was pinned at install
+  time, so an SDK fix could never reach it.
+- **`bun publish` runs `prepare`, and `prepare` needs bun2nix** — the SDK could not be published at
+  all. Also fixed: a corrupt committed `bun.lock` in plugin-kit.
+- **Decky client update.** `flatpak remote-info punktfunk-origin io.unom.Punktfunk` names no branch;
+  the remote publishes `stable` **and** `canary`, so the ref is ambiguous and flatpak refuses it —
+  ⚠ one branch being *installed* does not disambiguate, the ambiguity is on the remote. The call
+  failed on every box, every time, and returned `available=False`, which the panel rendered as good
+  news. Every query now names the ref in full via `_flatpak_ref()` (no subprocess), carrying the
+  **scope** too, so a system-wide install is no longer invisible to a check that hardcoded `--user`.
+  A check that cannot run now reports `client_error`.
+
+### Packaging
+
+- **The `punktfunk` group is created everywhere the udev rule needs it.** `60-punktfunk.rules`
+  chgrp's the usbip vhci attach/detach nodes to a dedicated group (security review 2026-08-05 M-4:
+  writing `attach` materialises an arbitrary emulated USB device, so it must not ride on `input`).
+  **Four of six install paths shipped that rule in 0.25.0 without creating the group** — chgrp
+  failed, nodes stayed `root:root 0644`, the virtual Deck pad silently never attached, and
+  `usermod -aG punktfunk` failed outright. Fixed in arch `post_upgrade()` (only `post_install` was
+  correct, so every box that reached 0.25.0 by `pacman -Syu` missed it), nix (`users.groups.punktfunk`
+  did not exist), the bazzite sysext (a group is host state and cannot ride an image), and the Steam
+  Deck scripts. deb and rpm were correct throughout.
+- **`punktfunk-gamescope` now builds for RPM and apt**, not Arch only.
+- **Arch release-rebuild prune** called a helper that cannot exist in a release rebuild. Together
+  with the FFmpeg 9 repackage this closes the 0.25.0-1 → 0.25.0-2 episode in the pipeline rather
+  than by hand.
+- **Steam Deck `update.sh` / `install.sh`.** The web step ran `bun install --frozen-lockfile` with
+  no `--ignore-scripts`, so web's `postinstall` (`bun2nix -o bun.nix`) rewrote a **tracked** file on
+  every update; the SDK step below it had always passed `--ignore-scripts`, and that asymmetry is
+  the whole bug. Now `--ignore-scripts` plus an explicit `bun run codegen` — provably equivalent,
+  since web's `prepare` is literally `"bun run codegen"` and `src/api/gen`, `src/paraglide` and
+  `src/routeTree.gen.ts` are gitignored. `--pull` restores `web/bun.nix` and `sdk/bun.nix` before
+  pulling, which is lossless by construction. ⚠ Deliberately **not** `git reset --hard`: `$SRC`
+  defaults to the operator's own checkout. Also: `web.env` secret hygiene — `chmod 600` sat inside
+  the create-only branch, so an install set up once and only updated since kept it world-readable.
+  ⚠ `packaging/debian/build-web-deb.sh`, `packaging/arch/PKGBUILD` and `packaging/rpm/punktfunk.spec`
+  still lack `--ignore-scripts` for web — harmless (throwaway build trees), left as follow-up.
+
+### Triage tooling
+
+**`--probe-decode` described a different device from the one that streams.** The RADV
+video-decode opt-in sat *after* the `--list-adapters` / `--probe-decode` / `--list-audio` / `--pair`
+early exits, so the triage tool never had it. Measured on a Deck, same binary back to back: bare
+`--probe-decode` printed "vulkan video decode: no", "driver decode ops: none (0x0)", "no queue
+family advertises VIDEO_DECODE"; with `RADV_PERFTEST=video_decode` in the environment, "YES" and
+"H.264, H.265, AV1, VP9". ⚠ **Any Deck triage that consulted it reached the opposite of the truth.**
+Hoisted to the top of `run`, ahead of every early exit.
+
+### PyroWave on Linux — Wave 2
+
+The program's own measurement, from patch 0005's header: `encode_gpu_synchronous` goes from ~2 ms
+to **15–18 ms at 95 % game load**, with the stream frame rate collapsing. PyroWave encodes on the
+same shader cores a game saturates; NVENC is immune because it has its own ASIC.
+
+- **PW1 — the GPU-priority lever had never fired on Linux.** The vendored patch requests an elevated
+  global-priority queue, gated `if (!inherit_info)` — and **only Windows leaves `inherit_info` null**
+  (`pyrowave_create_device_by_compat`, where Granite builds the device itself). Linux passes its own
+  create-infos, Granite's `get_existing_create_info()` hands them back, `create_device` takes the
+  inherit branch, and the whole block is skipped. Now wired natively in `open_inner`'s `DeviceHold`,
+  ladder REALTIME → HIGH → no-priority, stepping only on refusal; a refused class can never fail the
+  open. The extension probe reuses the `dev_ext_props` already fetched for `queue_family_foreign` and
+  takes KHR or the EXT alias — the same spelling pf-zerocopy probes, so the two cannot disagree.
+  ⭐ **Needs `CAP_SYS_NICE`**, which the packaging granted in `0.26.0-1`; without it the lever does
+  nothing.
+  🛑 **Corrected in `0.26.0-2`: the packaging no longer grants it, and must not.** Every channel that
+  did (Arch `.install`, RPM `%caps()`, the Bazzite sysext image, the deb postinst, the NixOS
+  `security.wrappers` entry) broke desktop streaming on KDE outright — field-reported on CachyOS and
+  Bazzite as `KWin does not expose zkde_screencast_unstable_v1 to this client`. KWin identifies a
+  client by resolving its `/proc/<pid>/exe` against an installed `.desktop`, and the kernel refuses
+  that readlink to any reader whose effective set is not a superset of the target's **permitted**
+  set (`cap_ptrace_access_check`) — KWin has no capabilities, so a capability-carrying host is
+  unidentifiable and the restricted globals are never advertised. Neither `prctl(PR_SET_DUMPABLE, 1)`
+  nor systemd `AmbientCapabilities=` rescues it; only an uncapped process is identifiable. The lever
+  therefore stays wired but unexercised on a stock install (the ladder degrades to default priority),
+  and is opt-in for gamescope-only hosts, which have no such identity check.
+- **PW5 — two encoder handles.** `Encoder::Impl` owns exactly one each of `wavelet_img_high_res`,
+  `bucket_buffer`, `meta_buffer`, `block_stat_buffer`, `payload_data`, `quant_buffer`, and
+  `Impl::encode` *opens* by discarding them (an image barrier with `VK_IMAGE_LAYOUT_UNDEFINED` as the
+  old layout, plus three `fill_buffer` clears). Two encodes submitted to one queue have **no**
+  execution dependency in Vulkan — submission order orders the start, not the completion — so N+1's
+  DWT would overwrite N's wavelet bands while N's block packing still reads them. Content-dependent
+  and silent. Overlap therefore means two handles alternated, one per slot. ⚠⚠ **The landmine:**
+  `sequence_count` also lives on `Impl`, and it is the **3-bit** counter stamped into every block
+  header. Two handles each counting 1,2,3… put 1,1,2,2,3,3… on the wire, and the decoder restarts a
+  frame only when the value *changes* — so a repeat reads as more blocks of the same frame. Depth is
+  **still 1**; the handles alternate with one in flight.
+- **PW3 — the fence wait moved out of submit.** PyroWave was the one backend waiting its fence inside
+  `submit`.
+- **PW7a — the jumbo leg was dead code.** quinn caps a peer's MTU-discovery search at
+  `min(MtuDiscoveryConfig::upper_bound, the other side's advertised max_udp_payload_size)`, and
+  `EndpointConfig::max_udp_payload_size` **defaults to 1472**. Nothing in the repo had ever touched
+  `EndpointConfig`, so raising the host's probe ceiling could never make discovery settle above 1472
+  — and the shipped mid-session grow's `settled >= sealed_datagram_bytes(target)` gate was
+  unreachable on **every path that has ever existed**. Two smaller contributors fixed with it: the
+  watcher stopped sampling the moment `settled >= 1472`, discarding the very climb the proof needs;
+  and a session sealed above the 1500-byte default was never checked against the path at all.
+
+  The advertisement is raised on the **client** endpoint under the same `jumbo_wire_mtu()` opt-in,
+  because it is not free: quinn sizes its endpoint receive buffer
+  `max_udp_payload_size × max_receive_segments × BATCH_SIZE` — on a GRO-capable Linux/Android client
+  that is ~2.9 MiB at the default and **~18 MiB at jumbo** (47 KiB → 288 KiB on Apple/Windows).
+  PyroWave is the codec that most wants this: it can never be re-keyed mid-stream (its client parses
+  chunk-aligned AUs in windows of the `Welcome` value, read once over the C ABI), so it should
+  *start* at the big shard. At an 8908-byte shard that is ~6× fewer datagrams per frame — **~49k → ~8k
+  pps at 550 Mb/s**.
+
+### Zero-copy capture
+
+- **The dmabuf latch conflated two causes with different lifetimes.** One `AtomicBool` served both
+  "the encoder repeatedly failed to import what this compositor allocates" (unrecoverable, a driver
+  fact) and "the dmabuf-only capture offer never negotiated" (which can just mean the compositor was
+  mid-restart). Sharing it made the second as permanent as the first: **one timeout, and every later
+  session on that host captured CPU frames until the process restarted** — including sessions against
+  a different compositor and a different node that had never failed at anything, with nothing said.
+  Now a `RawDmabufLatch` owning both: import failures stay sticky (unchanged 3-consecutive threshold);
+  negotiation timeouts get a retry budget of **2** — deliberately small, since each failure costs a
+  ~10 s stall the user pays in dead air; a capture that negotiates credits the budget back; and both
+  are keyed to a capture identity (node id + portal bit).
+- **The zero-copy path never asked for buffer headroom.** `build_dmabuf_buffers` set
+  `SPA_PARAM_BUFFERS_dataType` and stopped — no `SPA_PARAM_BUFFERS_buffers` at all, so the pool depth
+  every zero-copy safety argument rests on was entirely the producer's choice and we never expressed
+  a preference. Now asks for 8 (min 2, max 16) as a **Choice Range, deliberately not a fixed count**:
+  SPA intersects consumer and producer params, so a fixed 8 against a producer that can only afford 4
+  empties the intersection and the link stalls in "negotiating" with no error anywhere — ⚠ the exact
+  trap that once cost this codebase the entire Linux cursor channel, when a 256² cursor-meta max
+  failed to intersect Mutter's fixed 384². 8 buffers is ~133 ms of pool at 60 Hz and ~33 ms at 240 Hz;
+  16 is a ceiling, not a request (a 4K 4:4:4 buffer is ~25 MB).
+- **A PyroWave session could drop to CPU capture and log nothing.** The CPU-fallback warning was gated
+  on `backend_is_vaapi`, which reads the **host-global** encoder pref — but a PyroWave session is
+  negotiated **per session**, so on an NVIDIA/auto host that gate is false and the session fell out of
+  every arm of the negotiation log chain while paying a full-resolution CPU pixel touch every frame.
+  A degraded host and a healthy one produced identical logs. Now asks the per-session question
+  (`consumer_kind`), widened to every GPU consumer and excluding only the software encoder, whose
+  native input *is* CPU frames. ⚠ `pyrowave_session` must outrank `backend_is_vaapi`, because a
+  PyroWave pref flips `backend_is_vaapi` on too.
+
+### Steam-overlay input masking (Steam Deck)
+
+On a Deck in Gaming Mode the Steam menu and the QAM are driven by the **same physical controller** the
+client forwards, so opening either moved the game on the host as well — a second, invisible player.
+Steam Input masks a normal game here; it cannot mask us, because masking happens on Steam Input's
+virtual pad and we deliberately forward the **real** one (the virtual pad has no gyro, trackpads or
+paddles).
+
+⚠ **SDL's own gate cannot fire on a Deck.** SDL drops presses while a process has windows but no
+keyboard focus, and it is on by default — but gamescope resolves focus per Xwayland ctx and the client
+sits alone in its own, so the Steam overlay (which lives in the root ctx) never takes our X focus and
+no `FocusOut` is ever generated. Measured on glass: with the QAM open, X input focus inside the
+client's ctx stayed on its window for the whole 4 s while `GAMESCOPE_FOCUSED_APP` flipped to 769
+(Steam) and `GAMESCOPE_FOCUSED_APP_GFX` stayed on the app. **That pair of atoms is the signal.**
+
+⚠ `overlay_focus` watches them on the gamescope **root** ctx, which is *not* our own `$DISPLAY` under
+`--xwayland-count 2` — hence the socket-directory walk and the flatpak filesystem line.
+
+⚠⚠ Masking is deliberately **not** `set_forwarding`: that closes the slot and sends `GamepadRemove`,
+so the game would see a controller **unplug** every time somebody opened the QAM. Every slot stays
+open and only transitions stop, after flushing what the host believes is held (so a stick deflected at
+overlay-open stops steering instead of freezing at its last value). On the way back, held buttons are
+**adopted rather than replayed** — the A that picked a QAM row must not fire in the game as it closes
+— while axes *are* re-sent, since a stick has no press to ghost and SDL only speaks on change.
+
+### The `plugin` launch kind
+
+The 2026-08-05 review made `launch.kind = "command"` operator-only, and a reconcile refuses on the
+**first** offending entry — so rom-manager, whose every ROM is `<emulator> <args> <rom>`, stopped
+putting anything in the library at all. Playnite hit the same wall and was rescued with a typed kind
+the host resolves itself; there is no fixed scheme for "whichever emulator the operator configured,
+with the core and flags they chose", so that trick does not generalise.
+
+The entry now carries an **opaque key and nothing executable**, and the host asks the owning plugin
+what to run at launch time, over the loopback UI port and per-boot secret it already registered.
+⭐ **A stolen plugin token stops being command execution:** planting an entry is not enough, because
+the live plugin answers 404 for a key it never published. Nothing executable is persisted or served to
+a client, and an emulator that moved is picked up on the next launch rather than leaving a dead tile
+(same reasoning as `xbox` resolving its AUMID at launch time).
+
+⚠ **The host still spawns it**, because only the host can put the process where the stream can see it:
+on Linux that is either gamescope's own argv or a spawn carrying the session's compositor env, and the
+returned child is what session-game-lifetime tracks to know the game exited. A plugin spawning the
+emulator itself would land it outside both.
+
+### Verification status
+
+| | |
+|---|---|
+| gamescope 0006 | 6/6 exit 0 on a release build at the real spawn shape (`2752x2064@120 --steam --xwayland-count 1`); distro control SIGSEGVs |
+| Decky client update | on the Deck against the real install — pre-fix `available=False remote=''`, post-fix `available=True remote=ca010668` |
+| `--probe-decode` | on a Deck, same binary back to back, with and without the RADV opt-in |
+| Apple audio | builds on arm64-apple-ios17.0 (the triple that compiles the `#if os(iOS)` blocks — a plain `swift build` is macOS and skips them), arm64-apple-tvos17.0, macOS; 257 Swift tests |
+| Audio jitter | 10-minute Wi-Fi power-save simulation, ~2000 → 9 audible events |
+| 4:4:4 gate | test verified non-vacuous against the planted original defect |
+| Steam Deck scripts | `bash -n` + shellcheck 0.11.0 clean at `-S warning`; exec bits preserved |
+| Steam-overlay masking | on glass on a Deck — atom flip and X-focus non-flip both measured over a 4 s QAM open |
+| PyroWave depth 2 | exercised on real hardware **without shipping depth 2** (dedicated test, shipped depth stays 1) |
+| PW6 streamed AU | the trap is real, and at 2 % loss it costs exactly nothing |
+
+⏳ **Owed on glass:** iPhone + Bluetooth listen, Apple TV stats overlay, MacBook audio listen, the
+Deck HEVC/4:4:4 retest, a Windows wake-from-sleep cycle, and the PyroWave-under-game-load A/B on a
+Linux host with `CAP_SYS_NICE` actually granted — the number this whole wave is aimed at. ⚠ That
+last one now needs a **gamescope-only** host, or a hand-granted capability on a box you are not
+streaming the KDE desktop from: see the `0.26.0-2` correction under PW1 above.
+
+---
+
 ## v0.25.0
 
 407 commits since v0.24.0.
@@ -79,6 +499,20 @@ capability rode on `input`, which every gamepad guide tells users to join — bu
 arbitrary USB hardware. Operators must `usermod -aG punktfunk "$USER"` and re-login or the pad stops
 attaching. Ordinary virtual gamepads are unaffected.
 
+> **Known issue in 0.25.0, fixed after it.** Four of the six install paths shipped
+> `60-punktfunk.rules` — whose `RUN+=` does `chgrp punktfunk` on the vhci `attach`/`detach` nodes —
+> without ever creating the group, so the `chgrp` failed, the nodes stayed root-only, and the pad
+> silently never attached. The `usermod` above also fails outright on those boxes with *group
+> 'punktfunk' does not exist*. Affected: **Arch/CachyOS upgraded** rather than freshly installed
+> (`post_upgrade` called only `_ensure_update_group`), the **NixOS module** (no
+> `users.groups.punktfunk`), the **Bazzite sysext** (a group is host state and cannot ride an
+> image), and **Steam Deck source installs** (`scripts/steamdeck/install.sh`/`update.sh` handled
+> only `input`). The deb and rpm scriptlets were correct throughout — they run one `%post`/`postinst`
+> on install and upgrade alike. All four now create the group, and the two that know which user
+> runs the host (the Deck scripts and the NixOS module's `host.users`) add that user to it as well.
+> Workaround on an unpatched box:
+> `sudo groupadd --system punktfunk`, then the `usermod`, then re-login.
+
 **3. Plugins may no longer set `launch.command` or the pre-launch command.** Both run through a
 shell and are now operator-token only; a plugin that sets them is refused. Third-party plugins that
 populated them need updating — use the `launcher_ui` / `xbox` launch kinds instead.
@@ -437,6 +871,24 @@ refuses the upgrade instead of bricking the install. All seven libs are listed e
 `--as-needed` currently drops two: an unlinked soname is left bare by makepkg and satisfied by any
 ffmpeg, so listing it costs nothing and a future link picks up the bound automatically.
 
+🛑 **The v0.25.0 Arch packages shipped with that bound pointing at the WRONG FFmpeg — install
+`punktfunk-host 0.25.0-2` or newer.** The soname fix and the FFmpeg-9 build landed as one merge;
+the release tag was pushed four minutes later, while the CI builder image was still being
+rebuilt. arch.yml deliberately runs no `-Syu` ("the image's snapshot IS the build environment"),
+so the release was linked against FFmpeg 8 and published `libavcodec.so=62-64` — a bound no
+up-to-date Arch box can satisfy. It fails *safely* (pacman refuses; nothing bricks), but it fails
+**loudly and broadly**: pacman prepares one transaction, so an unsatisfiable dependency of ours
+stopped affected users' entire `pacman -Syu`. `0.25.0-2` is the identical source rebuilt against
+FFmpeg 9. Only Arch was exposed — every other format derives its dependency from the ELF at build
+time and could not disagree with itself this way.
+
+Two guards now stand where only a convention did. arch.yml compares the builder's libav
+`provides` against the live repos before building and `-Syu`s itself if they differ; and no
+package is published until a **pristine-`--dbpath`** `pacman -U --print` resolves it, which asks
+"would a real, up-to-date Arch box install this?" instead of "does the builder happen to satisfy
+it?" — the distinction that let this ship. Keeping `ci/arch-ci.Dockerfile` current is still the
+cheap path; the guards are the backstop.
+
 ### Linux playback filled the buffer ceiling
 
 The PipeWire playback callback sized its writes from the mapped buffer's **capacity** — PipeWire's

Cargo.lock

@@ -994,7 +994,7 @@ dependencies = [
 
 [[package]]
 name = "cursor-probe"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "pf-capture",
@@ -1114,7 +1114,7 @@ dependencies = [
 
 [[package]]
 name = "display-disturb"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "windows 0.62.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2358,7 +2358,7 @@ dependencies = [
 
 [[package]]
 name = "latency-probe"
-version = "0.25.0"
+version = "0.26.0"
 
 [[package]]
 name = "lazy_static"
@@ -2463,7 +2463,7 @@ dependencies = [
 
 [[package]]
 name = "libvpl-sys"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "bindgen",
  "cmake",
@@ -2498,7 +2498,7 @@ checksum = "0ceec5bc11778974d1bcb055b18002eba7f4b3518b6a0081b3af5f21666da9ad"
 
 [[package]]
 name = "loss-harness"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "punktfunk-core",
 ]
@@ -2988,7 +2988,7 @@ checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
 
 [[package]]
 name = "pf-bitstream"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "cros-codecs",
  "tracing",
@@ -2996,7 +2996,7 @@ dependencies = [
 
 [[package]]
 name = "pf-capture"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ashpd",
@@ -3017,7 +3017,7 @@ dependencies = [
 
 [[package]]
 name = "pf-client-core"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ash",
@@ -3047,11 +3047,12 @@ dependencies = [
  "wasapi",
  "windows 0.62.2 (git+https://github.com/microsoft/windows-rs?rev=acb5a1a7441033d9312b16842af02eb0c2b403dc)",
  "winreg",
+ "x11rb",
 ]
 
 [[package]]
 name = "pf-clipboard"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ashpd",
@@ -3069,7 +3070,7 @@ dependencies = [
 
 [[package]]
 name = "pf-console-ui"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ash",
@@ -3090,7 +3091,7 @@ dependencies = [
 
 [[package]]
 name = "pf-dxvadec"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "cros-codecs",
  "pf-bitstream",
@@ -3100,7 +3101,7 @@ dependencies = [
 
 [[package]]
 name = "pf-encode"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ash",
@@ -3124,7 +3125,7 @@ dependencies = [
 
 [[package]]
 name = "pf-frame"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "libc",
@@ -3136,7 +3137,7 @@ dependencies = [
 
 [[package]]
 name = "pf-gpu"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "pf-host-config",
@@ -3150,11 +3151,11 @@ dependencies = [
 
 [[package]]
 name = "pf-host-config"
-version = "0.25.0"
+version = "0.26.0"
 
 [[package]]
 name = "pf-inject"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ashpd",
@@ -3183,14 +3184,14 @@ dependencies = [
 
 [[package]]
 name = "pf-paths"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "tracing",
 ]
 
 [[package]]
 name = "pf-presenter"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ash",
@@ -3205,7 +3206,7 @@ dependencies = [
 
 [[package]]
 name = "pf-update"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "serde",
  "serde_json",
@@ -3213,7 +3214,7 @@ dependencies = [
 
 [[package]]
 name = "pf-update-check"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "base64",
@@ -3225,7 +3226,7 @@ dependencies = [
 
 [[package]]
 name = "pf-vaadec"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "cros-codecs",
  "pf-bitstream",
@@ -3234,7 +3235,7 @@ dependencies = [
 
 [[package]]
 name = "pf-vdisplay"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ashpd",
@@ -3267,7 +3268,7 @@ dependencies = [
 
 [[package]]
 name = "pf-vkdecode"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "ash",
  "cros-codecs",
@@ -3278,7 +3279,7 @@ dependencies = [
 
 [[package]]
 name = "pf-win-display"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "pf-paths",
@@ -3290,7 +3291,7 @@ dependencies = [
 
 [[package]]
 name = "pf-zerocopy"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ash",
@@ -3513,7 +3514,7 @@ dependencies = [
 
 [[package]]
 name = "punktfunk-cli"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "pf-client-core",
  "punktfunk-core",
@@ -3524,7 +3525,7 @@ dependencies = [
 
 [[package]]
 name = "punktfunk-client-android"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "android_logger",
  "jni",
@@ -3542,7 +3543,7 @@ dependencies = [
 
 [[package]]
 name = "punktfunk-client-linux"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "async-channel",
@@ -3559,7 +3560,7 @@ dependencies = [
 
 [[package]]
 name = "punktfunk-client-session"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "pf-client-core",
@@ -3574,7 +3575,7 @@ dependencies = [
 
 [[package]]
 name = "punktfunk-client-windows"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "async-channel",
  "mdns-sd",
@@ -3593,7 +3594,7 @@ dependencies = [
 
 [[package]]
 name = "punktfunk-core"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "aes-gcm",
  "bytes",
@@ -3625,7 +3626,7 @@ dependencies = [
 
 [[package]]
 name = "punktfunk-host"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "aes",
  "aes-gcm",
@@ -3710,7 +3711,7 @@ dependencies = [
 
 [[package]]
 name = "punktfunk-probe"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "mdns-sd",
@@ -3724,7 +3725,7 @@ dependencies = [
 
 [[package]]
 name = "punktfunk-tray"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "anyhow",
  "ksni",
@@ -3747,7 +3748,7 @@ checksum = "d55d956fa96f5ec02be2e13af0e20391a5aa83d6a074e3ad368959d0fab299ea"
 
 [[package]]
 name = "pyrowave-sys"
-version = "0.25.0"
+version = "0.26.0"
 dependencies = [
  "bindgen",
  "cmake",

Cargo.toml

@@ -57,7 +57,7 @@ exclude = [
 ndk = { path = "clients/android/native/vendor/ndk" }
 
 [workspace.package]
-version = "0.25.0"
+version = "0.26.0"
 edition = "2021"
 rust-version = "1.82"
 license = "MIT OR Apache-2.0"

api/openapi.json

@@ -10,7 +10,7 @@
       "name": "MIT OR Apache-2.0",
       "identifier": "MIT OR Apache-2.0"
     },
-    "version": "0.24.0"
+    "version": "0.25.0"
   },
   "paths": {
     "/api/v1/clients": {
@@ -997,7 +997,7 @@
           "library"
         ],
         "summary": "List the game library",
-        "description": "Every installed-store title (Steam, read from the host's local files — no Steam API key)\nmerged with the user's custom entries, sorted by title. Artwork fields are URLs the client\nfetches directly (the public Steam CDN for Steam titles). `?provider=` narrows to the\nentries a given external provider owns; `?platform=` to one platform (case-insensitive —\ninstalled-store titles are `PC`, custom/provider entries carry whatever was authored).",
+        "description": "Every installed-store title (Steam, read from the host's local files — no Steam API key)\nmerged with the user's custom entries, sorted by title. Artwork fields are URLs the client\nfetches directly (the public Steam CDN for Steam titles). `?provider=` narrows to the\nentries a given external provider owns; `?platform=` to one platform (case-insensitive —\ninstalled-store titles are `PC`, custom/provider entries carry whatever was authored).\n\n**The operator's own lane additionally sees the titles they have HIDDEN**, each carrying\n`hidden: true`; every other lane gets them filtered out upstream and cannot tell they exist. The\nconsole needs them to offer \"un-hide\", and it is the only surface that does.",
         "operationId": "getLibrary",
         "parameters": [
           {
@@ -1021,13 +1021,13 @@
         ],
         "responses": {
           "200": {
-            "description": "Unified library across all stores",
+            "description": "Unified library across all stores (the operator's lane also gets hidden entries, flagged)",
             "content": {
               "application/json": {
                 "schema": {
                   "type": "array",
                   "items": {
-                    "$ref": "#/components/schemas/GameEntry"
+                    "$ref": "#/components/schemas/OperatorGameEntry"
                   }
                 }
               }
@@ -1301,6 +1301,79 @@
         }
       }
     },
+    "/api/v1/library/hidden/{id}": {
+      "put": {
+        "tags": [
+          "library"
+        ],
+        "summary": "Hide or un-hide one library title",
+        "description": "Curation, not access control: a hidden title disappears from every play surface — the console\ngrid on a client, native clients, the GameStream app list, and launch resolution — while nothing\nis deleted and un-hiding restores it immediately. The operator's own console still lists it\n(flagged `hidden`) so it can be brought back.\n\nKeyed by the entry's stable `<store>:<external_id>` id, which survives re-scans and reconciles by\nconstruction (D2). The id is **not** validated against the current library on purpose: a title\ncan be legitimately absent at this moment (launcher closed, plugin mid-sync, drive unmounted),\nand refusing the operator's choice in that window would be worse than storing an id that\ncurrently matches nothing. Emits `library.changed` (source = the store) only on a real change.",
+        "operationId": "setLibraryEntryHidden",
+        "parameters": [
+          {
+            "name": "id",
+            "in": "path",
+            "description": "The library entry id (e.g. `steam:70`)",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/HiddenToggle"
+              }
+            }
+          },
+          "required": true
+        },
+        "responses": {
+          "200": {
+            "description": "Stored; the entry's visibility after the call",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/HiddenState"
+                }
+              }
+            }
+          },
+          "400": {
+            "description": "Empty entry id",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ApiError"
+                }
+              }
+            }
+          },
+          "401": {
+            "description": "Missing or invalid bearer token",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ApiError"
+                }
+              }
+            }
+          },
+          "500": {
+            "description": "Could not persist the settings",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ApiError"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
     "/api/v1/library/provider/{provider}": {
       "put": {
         "tags": [
@@ -5553,6 +5626,37 @@
           }
         }
       },
+      "HiddenState": {
+        "type": "object",
+        "description": "What `setLibraryEntryHidden` echoes back.",
+        "required": [
+          "id",
+          "hidden"
+        ],
+        "properties": {
+          "hidden": {
+            "type": "boolean",
+            "description": "Its visibility after the call."
+          },
+          "id": {
+            "type": "string",
+            "description": "The entry id the call addressed."
+          }
+        }
+      },
+      "HiddenToggle": {
+        "type": "object",
+        "description": "Request body for `setLibraryEntryHidden`.",
+        "required": [
+          "hidden"
+        ],
+        "properties": {
+          "hidden": {
+            "type": "boolean",
+            "description": "Whether this title should be hidden from every play surface."
+          }
+        }
+      },
       "HookEntry": {
         "type": "object",
         "description": "One hook: fire `run` and/or `webhook` when an event matching `on` (+ `filter`) occurs.",
@@ -6339,6 +6443,23 @@
           }
         }
       },
+      "OperatorGameEntry": {
+        "allOf": [
+          {
+            "$ref": "#/components/schemas/GameEntry"
+          },
+          {
+            "type": "object",
+            "properties": {
+              "hidden": {
+                "type": "boolean",
+                "description": "The operator hid this title ([`set_entry_hidden`]) — omitted when false, so the shape only\ngrows for entries that actually are hidden."
+              }
+            }
+          }
+        ],
+        "description": "A library entry plus the operator's own view of it — today, whether they hid it.\n\nA separate type rather than a field on [`GameEntry`] for two reasons. It keeps the visibility\nanswer out of the providers entirely: a store parser has no opinion on what the operator hid, and\nadding `hidden: false` to all eight construction sites would imply it does. More importantly it\nmakes the lane rule a TYPE guarantee instead of a discipline — `GET /library` answers\n`Vec<GameEntry>` on every lane but the operator's, so a hidden entry cannot leak to a paired\nclient by someone forgetting a filter; there is no field there to leak.\n\n`flatten` keeps the wire shape identical to a plain entry with one extra key, so the console\nparses one model either way."
+      },
       "PairedClient": {
         "type": "object",
         "description": "A paired (certificate-pinned) Moonlight client.",

ci/arch-ci.Dockerfile

@@ -19,6 +19,16 @@
 # 63-64), so it would simply refuse to install rather than start. Re-keying this image is the step
 # that makes the ffmpeg-9 bump actually reach the package — a Cargo.toml bump alone does nothing
 # here. Whenever Arch moves to an FFmpeg major, bump the date in the same commit.
+#
+# ⚠ AND KNOW WHY THAT WAS NOT ENOUGH: bumping this date only helps once docker.yml has actually
+# republished the image, and nothing sequences the two workflows. v0.25.0 was tagged four minutes
+# after the ffmpeg-9 merge, so the release build still pulled the FFmpeg-8 `:latest` and published
+# a punktfunk-host that no up-to-date Arch box could install — which blocks the user's ENTIRE
+# `pacman -Syu`, not just our package. arch.yml therefore no longer trusts this image on that one
+# axis: it compares the builder's libav sonames against the repos before building (and `-Syu`s
+# itself if they differ), and refuses to publish anything a pristine-db `pacman -U --print` says
+# is unsatisfiable. This file staying current is still the CHEAP path — those guards are the
+# backstop, not the plan.
 FROM docker.io/library/archlinux:base-devel
 
 # One transaction: the main build/runtime deps (first list) + the gamescope companion's

clients/android/app/src/main/kotlin/io/unom/punktfunk/App.kt

@@ -69,11 +69,14 @@ fun App(forceGamepadUi: Boolean = false) {
     // later manual Back out of the library is not undone by a stale value.
     var reopenLibraryHostId by remember { mutableStateOf<String?>(null) }
 
-    // Console (gamepad) mode mirrors the Apple client: the setting AND (a pad is attached OR this is
-    // a TV OR the dev force flag). Flips live as controllers connect/disconnect.
+    // Console (gamepad) mode mirrors the Apple client: the setting AND (its mode says Always OR a
+    // pad is attached OR this is a TV OR the dev force flag). Flips live as controllers
+    // connect/disconnect — unless the mode is Always, where it simply stays.
     val tv = remember { isTvDevice(context) }
     val controllerConnected by rememberControllerConnected()
-    val gamepadUi = gamepadUiActive(settings.gamepadUiEnabled, controllerConnected, tv, forceGamepadUi)
+    val gamepadUi = gamepadUiActive(
+        settings.gamepadUiEnabled, settings.gamepadUiMode, controllerConnected, tv, forceGamepadUi,
+    )
 
     // Publish the live session process-wide, so a `punktfunk://` link that arrives as a SECOND
     // activity instance (the normal case under `launchMode = standard`) can refuse it before that

clients/android/app/src/main/kotlin/io/unom/punktfunk/GamepadPalette.kt

@@ -67,7 +67,7 @@ class GamepadPalette(
         )
 
         /**
-         * The twelve shipped palettes: the brand default, five more dark fields, then six pale
+         * The thirteen shipped palettes: the brand default, six more dark fields, then six pale
          * ones. Cycling order runs dark → light, so stepping the row walks the range one way.
          */
         val ALL = listOf(
@@ -77,6 +77,22 @@ class GamepadPalette(
                 ground = Triple(0.075, 0.060, 0.160),
                 accent = Triple(0.525, 0.471, 0.961), light = false,
             ),
+            GamepadPalette(
+                // For OLED and AMOLED panels, where a black pixel is a pixel switched off — no
+                // glow, no power. The first two stops are literally (0,0,0), so the shaded half
+                // of the field is genuinely off rather than "very dark grey", and the ground is
+                // pure black too: the calm mix on the form screens lifts toward nothing. What is
+                // left is a faint indigo→violet ember in the bright corner. The accent stays the
+                // brand violet — focus has to be findable on black.
+                "oled", "OLED",
+                listOf(
+                    Triple(0.000, 0.000, 0.000), Triple(0.000, 0.000, 0.000),
+                    Triple(0.010, 0.020, 0.100), Triple(0.045, 0.016, 0.115),
+                    Triple(0.120, 0.024, 0.130),
+                ),
+                ground = Triple(0.0, 0.0, 0.0),
+                accent = Triple(0.525, 0.471, 0.961), light = false,
+            ),
             GamepadPalette(
                 // Deep indigo climbing through violet into a hot magenta.
                 "nebula", "Nebula",

clients/android/app/src/main/kotlin/io/unom/punktfunk/GamepadSettingsScreen.kt

@@ -665,6 +665,21 @@ internal fun buildSettingsRows(
             "Turn off to use the touch interface even with a controller connected.",
             s.gamepadUiEnabled,
         ) { update(s.copy(gamepadUiEnabled = it)) },
+    ) + listOfNotNull(
+        // WHEN the switch above takes over. Built only while it is ON: turn the switch off from
+        // this very screen and the row under the cursor would otherwise be one deciding nothing,
+        // on a screen that is itself about to disappear.
+        if (s.gamepadUiEnabled) {
+            choice(
+                "gamepadUIMode", GpTab.INTERFACE, null, "Show it",
+                "With a controller: the touch interface comes back when the last one " +
+                    "disconnects. Always keeps this layout either way — for a device that lives " +
+                    "docked to a TV. A TV itself is always in this mode regardless.",
+                GAMEPAD_UI_MODE_OPTIONS, s.gamepadUiMode,
+            ) { update(s.copy(gamepadUiMode = it)) }
+        } else {
+            null
+        },
     )
 }
 

clients/android/app/src/main/kotlin/io/unom/punktfunk/GamepadUi.kt

@@ -16,15 +16,35 @@ import androidx.compose.runtime.remember
 import androidx.compose.ui.platform.LocalContext
 import io.unom.punktfunk.kit.Gamepad
 
+/**
+ * [Settings.gamepadUiMode]: take over only while a controller is attached. The default, and what
+ * the switch meant when it was a lone Boolean.
+ */
+const val GAMEPAD_UI_WHEN_CONNECTED = "connected"
+
+/**
+ * [Settings.gamepadUiMode]: take over whenever the switch is on, pad or no pad — for a phone or
+ * tablet that lives docked to a TV, where the console layout is the one wanted and the pad is not
+ * always awake.
+ */
+const val GAMEPAD_UI_ALWAYS = "always"
+
 /**
  * Whether the controller-optimized "console" home (the host carousel + gamepad chrome) should
  * replace the touch UI — the Android mirror of the Apple client's `GamepadUIEnvironment.isActive`:
- * the user's [enabled] setting AND (a controller is attached OR this is a TV OR the dev [forced]
- * flag). A TV counts unconditionally — its remote/gamepad is the only input, so it's always the
- * console UI (as long as the setting is on).
+ * the user's [enabled] setting AND (the [mode] is [GAMEPAD_UI_ALWAYS] OR a controller is attached
+ * OR this is a TV OR the dev [forced] flag). A TV counts unconditionally — its remote/gamepad is
+ * the only input, so it's always the console UI (as long as the setting is on), which is why the
+ * mode row means nothing there. An unrecognized [mode] waits for a controller, so a value a newer
+ * client wrote can never strand this one in a layout it has no way back out of.
  */
-fun gamepadUiActive(enabled: Boolean, controllerConnected: Boolean, tv: Boolean, forced: Boolean): Boolean =
-    enabled && (controllerConnected || tv || forced)
+fun gamepadUiActive(
+    enabled: Boolean,
+    mode: String,
+    controllerConnected: Boolean,
+    tv: Boolean,
+    forced: Boolean,
+): Boolean = enabled && (mode == GAMEPAD_UI_ALWAYS || controllerConnected || tv || forced)
 
 /** True on a TV: the leanback/television feature or the TELEVISION ui-mode. */
 fun isTvDevice(context: Context): Boolean {

clients/android/app/src/main/kotlin/io/unom/punktfunk/Settings.kt

@@ -94,11 +94,20 @@ data class Settings(
     val touchMode: TouchMode = TouchMode.TRACKPAD,
     /**
      * Swap the whole home screen for the controller-optimized "console" UI (the host carousel +
-     * gamepad chrome) whenever a controller is connected — mirrors the Apple client's
-     * `gamepadUIEnabled`. On by default; turn it off to keep the touch UI even with a pad attached.
+     * gamepad chrome) — mirrors the Apple client's `gamepadUIEnabled`. On by default; turn it off
+     * to keep the touch UI even with a pad attached. WHEN it takes over is [gamepadUiMode].
      * A TV (leanback) is always in this mode regardless (its remote/pad is the only input).
      */
     val gamepadUiEnabled: Boolean = true,
+    /**
+     * When [gamepadUiEnabled] actually takes over — the cross-client `gamepad_ui_mode` pair,
+     * mirroring the Apple client's `gamepadUIMode`: `"connected"` (default, and what the switch
+     * has always meant) waits for a controller; `"always"` keeps the console UI with no pad in
+     * reach, for a phone or tablet that lives docked to a TV. Read only while [gamepadUiEnabled]
+     * is on, which is why both settings screens hide the row when the switch is off. Anything
+     * unrecognized resolves to `"connected"`. A TV ignores it — it is always in console mode.
+     */
+    val gamepadUiMode: String = GAMEPAD_UI_WHEN_CONNECTED,
     /**
      * Show the experimental game-library browser (the coverflow reached with Y from a saved host).
      * Fetched from the host's management API over mTLS; needs a paired host. Mirrors the Apple
@@ -107,9 +116,10 @@ data class Settings(
     val libraryEnabled: Boolean = true,
     /**
      * Which colour family the console (gamepad) UI's living backdrop drifts through — the
-     * cross-client `ui_palette` key: `"violet"` (the brand default), `"tide"`, `"forest"`,
-     * `"ember"`, `"rose"`, `"graphite"`. See [GamepadPalette], whose table and maths mirror the
-     * desktop console's and the Apple client's under the same names. Presentation only: nothing
+     * cross-client `ui_palette` key: `"violet"` (the brand default), then `"oled"`, `"nebula"`,
+     * `"abyss"`, `"ember"`, `"moss"`, `"graphite"`, then the six pale fields. See
+     * [GamepadPalette], whose table and maths mirror the desktop console's and the Apple
+     * client's under the same names. Presentation only: nothing
      * about a stream depends on it, so it is a device preference and never part of a profile.
      * An unknown value reads as the default rather than failing — a newer client may have shipped
      * a palette this build doesn't know.
@@ -303,6 +313,8 @@ class SettingsStore(context: Context) {
             // Migration: the pre-enum Boolean "trackpad_mode" (true = trackpad, false = direct).
             ?: if (prefs.getBoolean(K_TRACKPAD, true)) TouchMode.TRACKPAD else TouchMode.POINTER,
         gamepadUiEnabled = prefs.getBoolean(K_GAMEPAD_UI, true),
+        gamepadUiMode = prefs.getString(K_GAMEPAD_UI_MODE, GAMEPAD_UI_WHEN_CONNECTED)
+            ?: GAMEPAD_UI_WHEN_CONNECTED,
         libraryEnabled = prefs.getBoolean(K_LIBRARY, true),
         uiPalette = prefs.getString(K_UI_PALETTE, "violet") ?: "violet",
         lowLatencyMode = prefs.getBoolean(K_LOW_LATENCY, true),
@@ -344,6 +356,7 @@ class SettingsStore(context: Context) {
             .putString(K_STATS_VERBOSITY, s.statsVerbosity.name)
             .putString(K_TOUCH_MODE, s.touchMode.name)
             .putBoolean(K_GAMEPAD_UI, s.gamepadUiEnabled)
+            .putString(K_GAMEPAD_UI_MODE, s.gamepadUiMode)
             .putBoolean(K_LIBRARY, s.libraryEnabled)
             .putString(K_UI_PALETTE, s.uiPalette)
             .putBoolean(K_LOW_LATENCY, s.lowLatencyMode)
@@ -384,6 +397,7 @@ class SettingsStore(context: Context) {
         const val K_HUD = "stats_hud_enabled"
         const val K_TOUCH_MODE = "touch_mode"
         const val K_GAMEPAD_UI = "gamepad_ui_enabled"
+        const val K_GAMEPAD_UI_MODE = "gamepad_ui_mode"
         const val K_LIBRARY = "library_enabled"
         const val K_UI_PALETTE = "ui_palette"
 
@@ -778,6 +792,13 @@ fun smoothBufferOptions(hz: Int): List<Pair<Int, String>> {
     )
 }
 
+/** (stored value, label) for when the console UI takes over — the Apple client's table verbatim.
+ * Only offered while [Settings.gamepadUiEnabled] is on; a TV is in console mode either way. */
+val GAMEPAD_UI_MODE_OPTIONS = listOf(
+    GAMEPAD_UI_WHEN_CONNECTED to "With a controller",
+    GAMEPAD_UI_ALWAYS to "Always",
+)
+
 /** (mode, label) for the touch-input model. */
 val TOUCH_MODE_OPTIONS = listOf(
     TouchMode.TRACKPAD to "Trackpad",

clients/android/app/src/main/kotlin/io/unom/punktfunk/SettingsScreen.kt

@@ -592,11 +592,24 @@ private fun GeneralSettings(s: Settings, update: (Settings) -> Unit) {
         SettingsGroup("Interface") {
             ToggleRow(
                 title = "Controller-optimized UI",
-                subtitle = "Switch to the console home when a controller is connected. A TV " +
-                    "always uses it.",
+                subtitle = "Swap the touch home for the console home — the host carousel and " +
+                    "gamepad chrome. A TV always uses it.",
                 checked = s.gamepadUiEnabled,
                 onCheckedChange = { on -> update(s.copy(gamepadUiEnabled = on)) },
             )
+            // Only decides anything while the switch above is on, so it is HIDDEN rather than
+            // dimmed when it isn't — a picker whose every option changes nothing is worse than
+            // no picker, and this group is short enough that nothing jumps far.
+            if (s.gamepadUiEnabled) {
+                SettingDropdown(
+                    label = "Show it",
+                    options = GAMEPAD_UI_MODE_OPTIONS,
+                    selected = s.gamepadUiMode,
+                    caption = "With a controller: the touch home comes back when the last one " +
+                        "disconnects. Always keeps the console home either way — for a device " +
+                        "that lives docked to a TV.",
+                ) { v -> update(s.copy(gamepadUiMode = v)) }
+            }
         }
     }
 }

clients/android/app/src/test/kotlin/io/unom/punktfunk/GamepadPaletteTest.kt

@@ -33,14 +33,14 @@ class GamepadPaletteTest {
     fun tableMatchesTheOtherClients() {
         assertEquals(
             listOf(
-                "violet", "nebula", "abyss", "ember", "moss", "graphite",
+                "violet", "oled", "nebula", "abyss", "ember", "moss", "graphite",
                 "holo", "sunset", "bloom", "dawn", "mint", "opal",
             ),
             GamepadPalette.ALL.map { it.id },
         )
         // Dark fields lead, pale ones follow, so stepping the row walks one direction.
         val firstLight = GamepadPalette.ALL.indexOfFirst { it.light }
-        assertEquals(6, firstLight)
+        assertEquals(7, firstLight)
         assertTrue(GamepadPalette.ALL.drop(firstLight).all { it.light })
         // An unknown name is a newer client's palette, not an error.
         assertEquals("violet", GamepadPalette.named("chartreuse").id)
@@ -72,6 +72,25 @@ class GamepadPaletteTest {
         }
     }
 
+    /**
+     * OLED is the one palette whose selling point is measurable: it has to be genuinely black,
+     * not merely the darkest of the dark fields. The blob field this client draws samples the
+     * ramp at 0.15/0.40/0.65/0.90, so its darkest blob lands in the all-black head of the ramp.
+     */
+    @Test
+    fun oledIsActuallyBlack() {
+        val oled = GamepadPalette.named("oled")
+        assertEquals(Triple(0.0, 0.0, 0.0), oled.ground)
+        assertEquals(0f, oled.blobColors[0].red, 1e-6f)
+        assertEquals(0f, oled.blobColors[0].green, 1e-6f)
+        assertEquals(0f, oled.blobColors[0].blue, 1e-6f)
+        val mean = oled.stops.sumOf { luma(it) } / oled.stops.size
+        val darkestOther = GamepadPalette.ALL
+            .filter { it.id != "oled" && it.stops.isNotEmpty() }
+            .minOf { p -> p.stops.sumOf { luma(it) } / p.stops.size }
+        assertTrue("oled means $mean, barely under $darkestOther", mean < darkestOther / 2)
+    }
+
     /** A pale palette really is pale — its ink flips, so a mislabelled one is unreadable. */
     @Test
     fun palettesAreHonestAboutLightness() {

clients/android/app/src/test/kotlin/io/unom/punktfunk/GamepadSettingsRowsTest.kt

@@ -95,4 +95,47 @@ class GamepadSettingsRowsTest {
         // Drawn as a switch, and reading the persisted default.
         assertEquals(true, row(on, "dsCapture").toggled)
     }
+
+    /**
+     * The activation-mode row is a sub-setting of the Controller-optimized UI switch, so it is
+     * OFFERED only while that switch is on — hidden rather than dimmed, because with the switch
+     * off this whole screen is about to be replaced by the touch UI and a dimmed row there would
+     * be one last thing to step past on the way out.
+     */
+    @Test
+    fun `the activation-mode row follows the switch it belongs to`() {
+        fun ids(enabled: Boolean) = buildSettingsRows(
+            Settings(gamepadUiEnabled = enabled),
+            hasBodyVibrator = false, hasGyroscope = false, av1Capable = false,
+        ) {}.map { it.id }
+
+        val on = ids(enabled = true)
+        assertTrue("the mode row is missing", "gamepadUIMode" in on)
+        assertEquals(
+            "the mode belongs directly under the switch it qualifies",
+            on.indexOf("gamepadUI") + 1,
+            on.indexOf("gamepadUIMode"),
+        )
+        val off = ids(enabled = false)
+        assertFalse("the mode row must not outlive its switch", "gamepadUIMode" in off)
+        assertTrue("the switch itself stays, or it could never be turned back on", "gamepadUI" in off)
+    }
+
+    /** Stepping the mode row writes the shared `gamepad_ui_mode` value, and wraps on A. */
+    @Test
+    fun `the activation-mode row steps the shared key`() {
+        var s = Settings()
+        fun mode() = buildSettingsRows(
+            s, hasBodyVibrator = false, hasGyroscope = false, av1Capable = false,
+        ) { s = it }.first { it.id == "gamepadUIMode" }
+
+        assertEquals(GAMEPAD_UI_WHEN_CONNECTED, s.gamepadUiMode)
+        assertEquals("With a controller", mode().value)
+        assertFalse("already the first = thud", mode().adjust(-1))
+        assertTrue(mode().adjust(1))
+        assertEquals(GAMEPAD_UI_ALWAYS, s.gamepadUiMode)
+        // A from the last entry wraps home.
+        mode().activate()
+        assertEquals(GAMEPAD_UI_WHEN_CONNECTED, s.gamepadUiMode)
+    }
 }

clients/android/app/src/test/kotlin/io/unom/punktfunk/GamepadUiTest.kt

@@ -0,0 +1,53 @@
+package io.unom.punktfunk
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+/**
+ * [gamepadUiActive] is pure — table-tested over its inputs, and the mirror of the Apple client's
+ * `GamepadUIEnvironmentTests`. The two clients share the stored `gamepad_ui_mode` values, so a
+ * disagreement here is a device that behaves differently from the same setting.
+ */
+class GamepadUiTest {
+
+    /** The default mode is what the switch meant when it was a lone Boolean. */
+    @Test
+    fun whenConnectedWaitsForAPad() {
+        assertTrue(gamepadUiActive(true, GAMEPAD_UI_WHEN_CONNECTED, true, tv = false, forced = false))
+        assertFalse(gamepadUiActive(true, GAMEPAD_UI_WHEN_CONNECTED, false, tv = false, forced = false))
+        assertFalse(gamepadUiActive(false, GAMEPAD_UI_WHEN_CONNECTED, true, tv = false, forced = false))
+        assertFalse(gamepadUiActive(false, GAMEPAD_UI_WHEN_CONNECTED, false, tv = false, forced = false))
+        // A TV is in console mode whatever the mode says — its remote is the only input.
+        assertTrue(gamepadUiActive(true, GAMEPAD_UI_WHEN_CONNECTED, false, tv = true, forced = false))
+    }
+
+    /** Always drops the controller from the decision — but never the switch, which is the one
+     * way back to the touch UI. */
+    @Test
+    fun alwaysIgnoresThePadButNotTheSwitch() {
+        assertTrue(gamepadUiActive(true, GAMEPAD_UI_ALWAYS, false, tv = false, forced = false))
+        assertTrue(gamepadUiActive(true, GAMEPAD_UI_ALWAYS, true, tv = false, forced = false))
+        assertFalse(gamepadUiActive(false, GAMEPAD_UI_ALWAYS, false, tv = false, forced = false))
+        assertFalse(gamepadUiActive(false, GAMEPAD_UI_ALWAYS, true, tv = false, forced = false))
+    }
+
+    /** A value a newer client wrote waits for a pad rather than stranding this build in a
+     * layout it has no way back out of. */
+    @Test
+    fun anUnknownModeWaitsForAPad() {
+        assertFalse(gamepadUiActive(true, "whenever-i-say-so", false, tv = false, forced = false))
+        assertTrue(gamepadUiActive(true, "whenever-i-say-so", true, tv = false, forced = false))
+        assertFalse(gamepadUiActive(true, "", false, tv = false, forced = false))
+    }
+
+    /** The shipped default: the console UI still waits for a controller. */
+    @Test
+    fun theDefaultIsUnchangedBehaviour() {
+        val s = Settings()
+        assertTrue(s.gamepadUiEnabled)
+        assertEquals(GAMEPAD_UI_WHEN_CONNECTED, s.gamepadUiMode)
+        assertFalse(gamepadUiActive(s.gamepadUiEnabled, s.gamepadUiMode, false, tv = false, forced = false))
+    }
+}

clients/android/app/src/test/kotlin/io/unom/punktfunk/ProfilesTest.kt

@@ -77,6 +77,7 @@ class ProfilesTest {
 
         // Device-scope settings are not in the overlay at all, so no profile can move them.
         assertEquals(base.gamepadUiEnabled, out.gamepadUiEnabled)
+        assertEquals(base.gamepadUiMode, out.gamepadUiMode)
         assertEquals(base.libraryEnabled, out.libraryEnabled)
         assertEquals(base.autoWakeEnabled, out.autoWakeEnabled)
         assertEquals(base.sc2Capture, out.sc2Capture)

clients/apple/Sources/PunktfunkClient/ContentView.swift

@@ -99,6 +99,10 @@ struct ContentView: View {
     // with no (extended) controller attached tvOS falls back to HomeView as before.
     @ObservedObject private var gamepadManager = GamepadManager.shared
     @AppStorage(DefaultsKey.gamepadUIEnabled) private var gamepadUIEnabled = true
+    /// When the switch above takes over — "connected" (default) or "always". See
+    /// `GamepadUIEnvironment`.
+    @AppStorage(DefaultsKey.gamepadUIMode) private var gamepadUIMode =
+        GamepadUIEnvironment.modeWhenConnected
     /// Auto-wake on connect (Settings → General). On (default): a dial to an offline saved host
     /// fires Wake-on-LAN up front and falls into the "Waking…" wait if the dial fails. Off: connects
     /// go straight through with no wake. The explicit "Wake Host" action is unaffected either way.
@@ -113,7 +117,8 @@ struct ContentView: View {
     @Environment(\.scenePhase) private var scenePhase
     private var gamepadUIActive: Bool {
         GamepadUIEnvironment.isActive(
-            gamepadConnected: gamepadManager.active != nil, enabledSetting: gamepadUIEnabled)
+            gamepadConnected: gamepadManager.active != nil, enabledSetting: gamepadUIEnabled,
+            mode: gamepadUIMode)
     }
 
     // The body is split in two — `driven` (the screen plus its lifecycle drivers and sheets) and
@@ -901,6 +906,7 @@ struct ContentView: View {
     private var shortcutHintText: String {
         "Hold the remote's Back button — or L1+R1+Start+Select on a controller — to disconnect"
         + " · Touch surface moves the pointer · press clicks · Play/Pause right-clicks"
+        + " · Hold Play/Pause, or Select+X on a controller, for statistics"
     }
     private static let shortcutHintFont: CGFloat = 22 // read from the couch
     #endif

clients/apple/Sources/PunktfunkClient/Home/GamepadInk.swift

@@ -85,16 +85,40 @@ extension EnvironmentValues {
 }
 
 extension View {
-    /// Resolve the stored `ui_palette` and publish its ink to everything below. Applied by the
-    /// gamepad screens' common root so no individual view has to read the setting.
-    func gamepadPaletteInk() -> some View { modifier(GamepadInkModifier()) }
+    /// Resolve the stored `ui_palette` and publish its ink — AND the matching colour scheme — to
+    /// everything below. Applied by the gamepad screens' common root so no individual view has to
+    /// read the setting.
+    ///
+    /// `active` exists for the one surface that is the same view in both worlds: `LibraryView`
+    /// renders the coverflow under the gamepad UI and a plain grid without it. Passing `false`
+    /// publishes nothing, because the touch/desktop layouts sit on the SYSTEM background, where a
+    /// palette's scheme would invert their own system colours instead of matching them.
+    func gamepadPaletteInk(_ active: Bool = true) -> some View {
+        modifier(GamepadInkModifier(active: active))
+    }
 }
 
 private struct GamepadInkModifier: ViewModifier {
+    var active = true
     @AppStorage(DefaultsKey.uiPalette) private var paletteID = "violet"
+    /// The ambient scheme from ABOVE this modifier — what gets republished unchanged when the
+    /// gamepad UI isn't the one drawing, so `active: false` is a true no-op rather than a branch
+    /// that would change this view's identity.
+    @Environment(\.colorScheme) private var systemScheme
 
     func body(content: Content) -> some View {
-        content.environment(\.gamepadInk, GamepadInk.of(GamepadPalette.named(paletteID)))
+        let palette = GamepadPalette.named(paletteID)
+        return content
+            .environment(\.gamepadInk, active ? GamepadInk.of(palette) : .dark)
+            // The ink alone was never enough. Every SYSTEM-derived colour that lands on these
+            // screens — `.secondary` in a placeholder, a `.bordered` button's chrome, a
+            // NavigationStack's title, a material's frost — resolves against the DEVICE's
+            // appearance, which no part of this app had ever set. On iPhone and Mac that is often
+            // Light, so the pale palettes looked correct by accident; an Apple TV is Dark
+            // essentially always, so on tvOS every one of them came out WHITE on a pale field and
+            // the interface was unreadable. Publishing the scheme here — once, beside the ink it
+            // has to agree with — is what makes a pale palette mean "light" to UIKit too.
+            .environment(\.colorScheme, active ? (palette.light ? .light : .dark) : systemScheme)
     }
 }
 

clients/apple/Sources/PunktfunkClient/Home/LibraryView.swift

@@ -32,9 +32,12 @@ struct LibraryView: View {
     // setting off) every platform keeps the plain-grid presentation of this same view.
     @ObservedObject private var gamepadManager = GamepadManager.shared
     @AppStorage(DefaultsKey.gamepadUIEnabled) private var gamepadUIEnabled = true
+    @AppStorage(DefaultsKey.gamepadUIMode) private var gamepadUIMode =
+        GamepadUIEnvironment.modeWhenConnected
     private var gamepadUIActive: Bool {
         GamepadUIEnvironment.isActive(
-            gamepadConnected: gamepadManager.active != nil, enabledSetting: gamepadUIEnabled)
+            gamepadConnected: gamepadManager.active != nil, enabledSetting: gamepadUIEnabled,
+            mode: gamepadUIMode)
     }
     #endif
 
@@ -78,6 +81,16 @@ struct LibraryView: View {
                 }
             }
             #endif
+            #if os(iOS) || os(macOS) || os(tvOS)
+            // Published HERE, not just inside the coverflow, because the coverflow is only one of
+            // four things this view renders: the loading spinner, the error state and the empty
+            // state sit above it, as do the navigation title and toolbar. On iOS those are wrapped
+            // by GamepadLibraryScreen, which inks the whole thing; tvOS and macOS present this view
+            // directly in a NavigationStack, so under a pale palette every one of them kept the
+            // system's own (dark, on an Apple TV) chrome over a light field. Off when the gamepad
+            // UI isn't drawing — the plain grid belongs to the system background.
+            .gamepadPaletteInk(gamepadUIActive)
+            #endif
     }
 
     @ViewBuilder private var content: some View {

clients/apple/Sources/PunktfunkClient/Settings/GamepadSettingsView.swift

@@ -81,6 +81,9 @@ struct GamepadSettingsView: View {
     @AppStorage(DefaultsKey.hudPlacement) private var hudPlacement = HUDPlacement.topTrailing.rawValue
     @AppStorage(DefaultsKey.libraryEnabled) private var libraryEnabled = true
     @AppStorage(DefaultsKey.gamepadUIEnabled) private var gamepadUIEnabled = true
+    /// When the switch above takes over — the row is only built while it is on.
+    @AppStorage(DefaultsKey.gamepadUIMode) private var gamepadUIMode =
+        GamepadUIEnvironment.modeWhenConnected
     /// The gamepad UI's background colour family — the backdrop BEHIND this screen re-colours as
     /// the row steps, which is why the picker lives here and not in a sheet.
     @AppStorage(DefaultsKey.uiPalette) private var paletteID = "violet"
@@ -659,6 +662,21 @@ struct GamepadSettingsView: View {
                 detail: "Turn off to use the touch interface even with a controller connected.",
                 value: $gamepadUIEnabled),
         ]
+        // WHEN the switch above takes over. Built only while it is on: with the switch off this
+        // screen is unreachable in the first place (no gamepad UI to open it from), so a row
+        // that decides nothing would exist purely to be found in a screenshot.
+        if gamepadUIEnabled, let at = list.firstIndex(where: { $0.id == "gamepadUI" }) {
+            list.insert(
+                choiceRow(
+                    id: "gamepadUIMode", tab: .interface, icon: "gamecontroller.circle",
+                    label: "Show it",
+                    detail: "With a controller: the touch interface comes back when the last one "
+                        + "disconnects. Always keeps this layout either way — for a device that "
+                        + "lives on a TV.",
+                    options: SettingsOptions.gamepadUIModes, current: gamepadUIMode
+                ) { gamepadUIMode = $0 },
+                at: at + 1)
+        }
         #if os(macOS)
         // The windowed safe-present toggle slots in after "Smoothness buffer" (staying inside
         // the Video tab) — macOS only, mirroring the touch SettingsView's Presentation row
@@ -707,6 +725,14 @@ struct GamepadSettingsView: View {
                 at: anchor + 1)
         }
         #endif
+        // The smoothness buffer only decides anything under Smoothness. Every other settings
+        // surface — touch, tvOS, the GTK and WinUI shells — hides it under Lowest latency; this
+        // screen alone left it live and steppable, which is a row that thuds or silently stores
+        // a value nothing reads. Removed here rather than omitted from the literal above so the
+        // macOS safe-present insertion can still anchor on it.
+        if presentPriority != "smooth" {
+            list.removeAll { $0.id == "smoothBuffer" }
+        }
         return list + profileRows
     }
 

clients/apple/Sources/PunktfunkClient/Settings/SettingsOptions.swift

@@ -53,6 +53,14 @@ enum SettingsOptions {
     static let hudPlacements: [(label: String, tag: String)] =
         HUDPlacement.allCases.map { ($0.label, $0.rawValue) }
 
+    /// When the gamepad UI takes over (`DefaultsKey.gamepadUIMode`) — only meaningful while
+    /// `gamepadUIEnabled` is on, so every surface that offers it hides the row when the switch
+    /// is off rather than showing a picker that decides nothing.
+    static let gamepadUIModes: [(label: String, tag: String)] = [
+        ("With a controller", GamepadUIEnvironment.modeWhenConnected),
+        ("Always", GamepadUIEnvironment.modeAlways),
+    ]
+
     /// Presentation intent (`DefaultsKey.presentPriority` — the 2026-07 rebuild that replaced
     /// the visible stage picker with intent; see SessionPresenter's PresentPriority and
     /// design/apple-presentation-rebuild.md). The stage ladder survives only as the hidden

clients/apple/Sources/PunktfunkClient/Settings/SettingsView+Sections.swift

@@ -724,11 +724,24 @@ extension SettingsView {
             #endif
             #if !os(tvOS)
             if !inProfileScope {
-                described("With a controller connected, the host list and library switch to a "
-                    + "controller-friendly layout — larger focus targets, a swipeable cover "
-                    + "browser.") {
+                described("The host list and library switch to a controller-friendly layout — "
+                    + "larger focus targets, a swipeable cover browser.") {
                     Toggle("Gamepad-optimized browsing", isOn: $gamepadUIEnabled)
                 }
+                // Only meaningful while the switch above is on, so it is HIDDEN rather than
+                // disabled when it isn't: a picker whose every option decides nothing is worse
+                // than no picker, and this Section is short enough that nothing jumps far.
+                if gamepadUIEnabled {
+                    described("With a controller: the touch interface comes back when the last "
+                        + "one disconnects. Always keeps the controller-friendly layout either "
+                        + "way — for a device that lives on a TV.") {
+                        Picker("Show it", selection: $gamepadUIMode) {
+                            ForEach(SettingsOptions.gamepadUIModes, id: \.tag) { option in
+                                Text(option.label).tag(option.tag)
+                            }
+                        }
+                    }
+                }
             }
             #endif
             #if DEBUG && !os(tvOS)

clients/apple/Sources/PunktfunkClient/Settings/SettingsView.swift

@@ -75,6 +75,13 @@ struct SettingsView: View {
     @AppStorage(DefaultsKey.hudPlacement) var hudPlacement = HUDPlacement.topTrailing.rawValue
     @ObservedObject var gamepads = GamepadManager.shared
     @AppStorage(DefaultsKey.gamepadUIEnabled) var gamepadUIEnabled = true
+    /// When the switch above takes over — read (and shown) only while it is on.
+    @AppStorage(DefaultsKey.gamepadUIMode) var gamepadUIMode =
+        GamepadUIEnvironment.modeWhenConnected
+    /// The gamepad UI's background palette. Edited here on tvOS only (see `tvBody`) — every other
+    /// platform reaches it through the gamepad settings screen, which an Apple TV without a
+    /// controller cannot open.
+    @AppStorage(DefaultsKey.uiPalette) var uiPalette = "violet"
     @AppStorage(DefaultsKey.autoWake) var autoWakeEnabled = true
     @AppStorage(DefaultsKey.backgroundKeepAlive) var backgroundKeepAlive = false
     @AppStorage(DefaultsKey.backgroundTimeoutMinutes) var backgroundTimeoutMinutes = 10
@@ -488,6 +495,22 @@ struct SettingsView: View {
                 TVSelectionRow(
                     title: "Gamepad-optimized browsing",
                     options: [("On", "on"), ("Off", "off")], selection: gamepadUIEnabledTag)
+                // Hidden while the switch above is off — see the touch settings' identical gate.
+                if gamepadUIEnabled {
+                    TVSelectionRow(
+                        title: "Show it",
+                        options: SettingsOptions.gamepadUIModes, selection: $gamepadUIMode)
+                    // The Apple TV's ONLY route to the shared `ui_palette`. Everywhere else the
+                    // Background row lives on the gamepad settings screen, which is reached from
+                    // the gamepad launcher — and on tvOS that launcher needs an extended-profile
+                    // controller, so an Apple TV driven by the Siri Remote alone could not reach
+                    // the palettes at all. It belongs beside "Show it" because both describe the
+                    // same interface: this row is what that interface looks like once it is up.
+                    TVSelectionRow(
+                        title: "Background",
+                        options: GamepadPalette.all.map { (label: $0.name, tag: $0.id) },
+                        selection: $uiPalette)
+                }
                 tvCaption(Self.controllersFooter)
                 NavigationLink("About") { AboutView() }
                     .padding(.top, 8)

clients/apple/Sources/PunktfunkClient/Support/GlassStyle.swift

@@ -95,24 +95,19 @@ private struct ConsoleGlass<S: Shape>: ViewModifier {
     private var materialWash: Color { ink.glass(ink.isLight ? 0.55 : 0.40) }
 
     func body(content: Content) -> some View {
+        // The scheme goes on the WHOLE modified view, not just the fill inside `.background {}`.
+        // Scoped to the fill it frosts the material correctly and stops there, so a system colour
+        // in the row's own content (a `.secondary` label, a `.bordered` button) still resolved
+        // against the device appearance — which is how the pale palettes came out light-on-light
+        // on tvOS, whose appearance is always Dark. The 26 branch had it right all along; the
+        // tvOS and pre-26 branches were the odd ones out.
         #if os(tvOS)
         // ALWAYS the material fallback on tvOS: the gamepad settings list is 15+ of these
         // surfaces, and live Liquid Glass per row made the whole screen visibly laggy on the
         // Apple TV's GPU (same class of call GlassProminentButton already makes — glass fights
         // the 10-foot platform). The wash and tint ride overlays — two flat fills, no GPU cost.
-        content.background {
-            shape.fill(.ultraThinMaterial)
-                .environment(\.colorScheme, scheme)
-                .overlay { shape.fill(materialWash) }
-                .overlay {
-                    if let tint { shape.fill(tint) }
-                }
-        }
-        #else
-        if #available(iOS 26, macOS 26, *) {
-            content.glassEffect(glass, in: shape).environment(\.colorScheme, scheme)
-        } else {
-            content.background {
+        content
+            .background {
                 shape.fill(.ultraThinMaterial)
                     .environment(\.colorScheme, scheme)
                     .overlay { shape.fill(materialWash) }
@@ -120,6 +115,21 @@ private struct ConsoleGlass<S: Shape>: ViewModifier {
                         if let tint { shape.fill(tint) }
                     }
             }
+            .environment(\.colorScheme, scheme)
+        #else
+        if #available(iOS 26, macOS 26, *) {
+            content.glassEffect(glass, in: shape).environment(\.colorScheme, scheme)
+        } else {
+            content
+                .background {
+                    shape.fill(.ultraThinMaterial)
+                        .environment(\.colorScheme, scheme)
+                        .overlay { shape.fill(materialWash) }
+                        .overlay {
+                            if let tint { shape.fill(tint) }
+                        }
+                }
+                .environment(\.colorScheme, scheme)
         }
         #endif
     }
@@ -173,11 +183,14 @@ private struct ConsoleGlassBackground<S: Shape>: ViewModifier {
                     in: shape)
                 .environment(\.colorScheme, scheme)
         } else {
-            content.background {
-                shape.fill(.regularMaterial)
-                    .environment(\.colorScheme, scheme)
-                    .overlay { shape.fill(ink.glass(ink.isLight ? 0.55 : 0.40)) }
-            }
+            // Same hoist as ConsoleGlass: the content needs the scheme too, not only the frost.
+            content
+                .background {
+                    shape.fill(.regularMaterial)
+                        .environment(\.colorScheme, scheme)
+                        .overlay { shape.fill(ink.glass(ink.isLight ? 0.55 : 0.40)) }
+                }
+                .environment(\.colorScheme, scheme)
         }
     }
 }

clients/apple/Sources/PunktfunkKit/Audio/AudioRing.swift

@@ -16,11 +16,17 @@ import os
 /// (`punktfunk_core::audio::JitterPolicy`): a slow depth average that sits above target for a
 /// sustained window sheds ONE 5 ms frame with a crossfade, and the hard cap is only a backstop.
 ///
-/// **Adaptive depth.** The target is a floor, not a constant: repeated genuine underruns grow it
-/// a step at a time (`noteRead`, mirroring `JitterPolicy::note_read`) up to `maxTargetMS`, and a
-/// long quiet spell relaxes it back toward the base — so a session on Wi-Fi that bunches arrivals
-/// deepens until it stops crackling, while a clean LAN keeps the tight base latency. Keep the
-/// constants here in step with `JitterTuning.COREAUDIO`.
+/// **Adaptive depth.** The target is a floor, not a constant: a NEAR-MISS — a read served with
+/// less than one frame left over — grows it a step BEFORE anything was audible, repeated genuine
+/// underruns grow it too (`noteRead`, mirroring `JitterPolicy::note_read`) up to `maxTargetMS`,
+/// and a long quiet spell relaxes it back toward the base — so a session on Wi-Fi that bunches
+/// arrivals deepens until it stops crackling, while a clean LAN keeps the tight base latency.
+/// Growth only raises a promise; the one thing that re-banks real depth is a re-prime, so an
+/// underrun while the ring is HOLLOW (depth average far below the target) re-primes at once,
+/// spending the click it already cost on the whole refill. Every shrink is armed as a PROBE:
+/// answered by an underrun or near-miss within its window, it is undone on the spot, and a
+/// failed sync-driven shrink is not retried for a growing backoff. Keep the constants here in
+/// step with `JitterTuning.COREAUDIO`.
 ///
 /// **A/V sync.** On top of all that the depth can be STEERED, by `setSyncTarget` from the drain
 /// thread's `AvSync` — because a ring that is the right depth for the link is not thereby the
@@ -58,9 +64,29 @@ final class AudioRing: @unchecked Sendable {
     /// target normally relaxes only after a long spell because, absent other evidence, the only
     /// thing that can justify giving up hard-won slack is time; a sync request IS that evidence —
     /// a measurement saying the extra depth is costing alignment right now — so a smaller target
-    /// gets tested sooner. Wrong guesses are cheap and self-correcting (one underrun and the
-    /// growth path takes it straight back). Mirrors `SHRINK_QUIET_SYNC_MS`.
+    /// gets tested sooner. Mirrors `SHRINK_QUIET_SYNC_MS`.
     private static let shrinkQuietSyncMS = 5_000
+    /// Post-read depth below which a served callback counts as a NEAR-MISS: the device got its
+    /// samples, but with less than one protocol frame left in hand — the same evidence as an
+    /// underrun, except nobody heard it yet, so the target grows BEFORE the click instead of
+    /// after the third one. Mirrors `NEAR_MISS_MARGIN_MS`.
+    private static let nearMissMarginMS = frameMS
+    /// How long a shrink remains a PROBE, in consumed audio: an underrun or near-miss inside
+    /// this window means the shrink was wrong, and the previous target is restored at once.
+    /// Mirrors `SHRINK_PROBE_MS`.
+    private static let shrinkProbeMS = 5_000
+    /// How long a failed probe keeps the sync loop from driving another shrink — without it the
+    /// loop pays an audible starvation event every `shrinkQuietSyncMS` on any link whose jitter
+    /// genuinely needs the depth, forever. Doubles per consecutive failure, capped; a probe that
+    /// survives its window resets it. Mirror `SYNC_BACKOFF_MS` / `SYNC_BACKOFF_MAX_MS`.
+    private static let syncBackoffMS = 60_000
+    private static let syncBackoffMaxMS = 480_000
+    /// A ring is HOLLOW when its depth AVERAGE sits this far below the target: growth only ever
+    /// raises the promise, and the one thing that re-banks real depth is a re-prime — so an
+    /// underrun in a hollow ring re-primes AT ONCE, spending the click it already cost on the
+    /// whole refill instead of riding the knife edge one click per bunching period. Mirrors
+    /// `DEPRIME_DEBT_MS`.
+    private static let deprimeDebtMS = growStepMS
 
     private var buf: [Float]
     private var readIdx = 0
@@ -87,6 +113,24 @@ final class AudioRing: @unchecked Sendable {
     /// `nil` — the default, and what an un-wired session keeps — reproduces the pre-sync
     /// behaviour exactly, so this ring could adopt sync without the other three diverging.
     private var syncTarget: Int?
+    /// This read was served with less than `nearMissMarginMS` left over (set in `read`,
+    /// consumed by `noteRead`).
+    private var nearMiss = false
+    /// A near-miss already grew the target this window — one step per window, so a bunching
+    /// episode (a RUN of consecutive near-misses while the ring refills) buys one measured
+    /// step, not a sprint to the ceiling.
+    private var nearMissGrown = false
+    /// The depth average runs a `deprimeDebtMS` debt against the target (set in `read`): an
+    /// underrun should re-prime at once instead of waiting out the hysteresis.
+    private var hollow = false
+    /// Interleaved samples left in the current shrink-probe window (0 = no probe outstanding).
+    private var probeRun = 0
+    /// The live target before the probed shrink, restored if the probe fails.
+    private var probePrevTarget = 0
+    /// Interleaved samples before the sync loop may drive another shrink (0 = allowed now).
+    private var syncBackoffRun = 0
+    /// Length of the NEXT backoff, in ms — doubles per consecutive failed probe, capped.
+    private var syncBackoffLenMS = AudioRing.syncBackoffMS
     /// The sync loop's smoothed offset in ms, STORED not computed: the ring owns the depth but has
     /// no timestamps, so the drain thread (which has both a packet's `pts_ns` and the video leg)
     /// hands the number back for reporting. Mirrors `NativeClient::audio_av_offset_ms`.
@@ -121,8 +165,15 @@ final class AudioRing: @unchecked Sendable {
     /// then return the CAP — i.e. quietly below the continuity floor, inverting the very ordering
     /// this exists to guarantee, on exactly the awkward hardware it exists to survive. (Rust's
     /// `Ord::clamp` announces the same condition by panicking; Swift would just get it wrong.)
-    private var target: Int {
-        let floor = max(targetLive, renderQuantum + Self.frameMS * perMS)
+    private var target: Int { target(lift: renderQuantum) }
+
+    /// The effective target with an explicit quantum lift. The property above uses the high-water
+    /// `renderQuantum` (priming must survive the biggest callback seen); the hollow check in
+    /// `read` passes the CURRENT callback instead, mirroring the Rust side's `want` — a one-off
+    /// oversized read would otherwise inflate the debt threshold forever and turn the very next
+    /// late packet into a full re-prime.
+    private func target(lift quantum: Int) -> Int {
+        let floor = max(targetLive, quantum + Self.frameMS * perMS)
         guard let want = syncTarget else { return floor }
         let cap = max(Self.hardCapMS * perMS, floor)
         return min(max(want, floor), cap)
@@ -211,12 +262,24 @@ final class AudioRing: @unchecked Sendable {
             if available >= target {
                 primed = true
                 emptyReads = 0
+                // The refill just banked this much: seed the average with it rather than letting
+                // it climb from wherever the drought left it — a freshly-primed ring would
+                // otherwise read as hollow for the EWMA's whole settling time, and the FIRST
+                // late packet would re-prime a ring that is actually full.
+                depthAvg = Double(available)
             } else {
                 for i in 0..<count { out[i] = 0 }
                 return
             }
         }
 
+        // Hollow: the depth AVERAGE runs a debt against the target — the promise has been raised
+        // but the depth was never re-banked (see `deprimeDebtMS`). Judged on the average, not
+        // this instant: a single late packet empties the ring for a callback without making it
+        // hollow, and must keep the consecutive-empties hysteresis. Lifted by THIS callback's
+        // size, not the high-water quantum — see `target(lift:)`.
+        hollow = depthAvg + Double(Self.deprimeDebtMS * perMS) < Double(target(lift: count))
+
         // Drift correction: shed exactly one frame, crossfaded, once the AVERAGE has sat above
         // the threshold for the sustain window. Anything shorter is jitter and must be left alone.
         if depthAvg > Double(target + Self.shedExcessMS * perMS) {
@@ -240,6 +303,9 @@ final class AudioRing: @unchecked Sendable {
         if n < count {
             for i in n..<count { out[i] = 0 }
         }
+        // Near-miss: served in full, but with less than one frame left over — the next callback
+        // starves unless a packet lands within one frame time.
+        nearMiss = n == count && writeIdx - readIdx < Self.nearMissMarginMS * perMS
         noteRead(ranShort: n < count, count: count)
     }
 
@@ -254,32 +320,84 @@ final class AudioRing: @unchecked Sendable {
         if windowRun >= Self.growWindowMS * perMS {
             windowRun = 0
             underrunsInWindow = 0
+            nearMissGrown = false
+        }
+        syncBackoffRun = max(0, syncBackoffRun - count)
+        var restored = false
+        if probeRun > 0 {
+            probeRun = max(0, probeRun - count)
+            if ranShort || nearMiss {
+                // The probe FAILED: the link answered a shrink with (nearly) starving the ring.
+                // Take the depth straight back — re-learning it three audible underruns at a
+                // time is what made the sync-vs-growth tug-of-war audible — and keep the sync
+                // loop from probing again for a while, doubling per consecutive failure. The
+                // residual A/V offset is reported instead; continuity outranks sync. The
+                // restore CONSUMES this event as growth evidence: it answered a depth the ring
+                // is no longer at, so growing past the proven target on top would overshoot.
+                probeRun = 0
+                targetLive = max(targetLive, probePrevTarget)
+                syncBackoffRun = syncBackoffLenMS * perMS
+                syncBackoffLenMS = min(syncBackoffLenMS * 2, Self.syncBackoffMaxMS)
+                restored = true
+            } else if probeRun == 0 {
+                // Survived the whole window: the shallower depth is genuinely safe here, so the
+                // next probe starts from a clean slate.
+                syncBackoffLenMS = Self.syncBackoffMS
+            }
         }
         if ranShort {
             quietRun = 0
             emptyReads += 1
             underrunCount += 1
-            if emptyReads >= Self.deprimeAfter {
+            if emptyReads >= Self.deprimeAfter || hollow {
+                // The consecutive-empties hysteresis protects a FULL ring from one late packet.
+                // A hollow ring is the opposite case: the target has been raised but the depth
+                // never re-banked (growth is a promise; only a re-prime cashes it), and riding
+                // that out is a click per bunching period, forever. The click just heard has
+                // already paid for the refill — take it now.
                 primed = false
                 emptyReads = 0
             }
-            underrunsInWindow += 1
+            if !restored {
+                underrunsInWindow += 1
+            }
             if underrunsInWindow >= Self.growUnderruns {
                 underrunsInWindow = 0
                 windowRun = 0
                 targetLive = min(targetLive + Self.growStepMS * perMS, Self.maxTargetMS * perMS)
             }
+        } else if nearMiss {
+            // Came within one frame of an underrun — the same evidence as one, heard by no one.
+            // Growing here, BEFORE the click, is what "no audible jitter" means: waiting for
+            // the third audible underrun means the user heard two. One step per window (a
+            // bunching episode is a RUN of near-misses while the ring refills, and must buy one
+            // measured step, not a sprint to the ceiling); if it worsens into real underruns
+            // the path above takes over. A near-miss is pressure, not quiet.
+            quietRun = 0
+            emptyReads = 0
+            if !nearMissGrown, !restored {
+                nearMissGrown = true
+                targetLive = min(targetLive + Self.growStepMS * perMS, Self.maxTargetMS * perMS)
+            }
         } else {
             emptyReads = 0
             quietRun += count
             // Without a sync request, time is the only evidence that hard-won slack is no longer
             // needed, so a grown target waits out the long window. A request for less IS evidence,
             // and without this branch a ring that ratcheted to the ceiling during a transient would
-            // hold audio a ceiling's worth late for minutes after the cause had gone.
-            let quietNeeded = syncWantsLess ? Self.shrinkQuietSyncMS : Self.shrinkQuietMS
+            // hold audio a ceiling's worth late for minutes after the cause had gone. Every shrink
+            // is armed as a PROBE — answered by an underrun or near-miss it is undone at once (see
+            // above), and a failed sync-driven guess is not retried for a backoff.
+            let syncShrink = syncWantsLess && syncBackoffRun == 0
+            let quietNeeded = syncShrink ? Self.shrinkQuietSyncMS : Self.shrinkQuietMS
             if quietRun >= quietNeeded * perMS {
                 quietRun = 0
+                let prev = targetLive
                 targetLive = max(targetLive - Self.growStepMS * perMS, Self.targetMS * perMS)
+                if targetLive < prev {
+                    probeRun = Self.shrinkProbeMS * perMS
+                    probePrevTarget = prev
+                }
             }
         }
     }

clients/apple/Sources/PunktfunkKit/Audio/SessionAudio.swift

@@ -79,6 +79,13 @@ public final class SessionAudio {
     /// session's activate.
     private static let sessionQueue = DispatchQueue(label: "io.unom.punktfunk.audio.session")
     #endif
+    #if os(iOS)
+    /// Live only for a `.playAndRecord` session: the token for the route-change observer that
+    /// keeps the BUILT-IN output on the speaker rather than the earpiece (see
+    /// `steerBuiltInOutputToSpeaker`). A `.playback` session already prefers the speaker and
+    /// never needs steering, so the mic-off path installs nothing. Guarded by `stateLock`.
+    private var routeObserver: NSObjectProtocol?
+    #endif
 
     public init(connection: PunktfunkConnection) {
         self.connection = connection
@@ -89,6 +96,11 @@ public final class SessionAudio {
     /// Engine teardown still belongs to stop().
     deinit {
         flag.stop()
+        #if os(iOS)
+        // The observer only holds self weakly, so we can be deinited with it still registered;
+        // drop the token here too rather than leaking it when an owner skips stop().
+        if let routeObserver { NotificationCenter.default.removeObserver(routeObserver) }
+        #endif
     }
 
     /// Start playback (and, if enabled+authorized, the mic uplink). Empty UIDs = system default
@@ -138,11 +150,29 @@ public final class SessionAudio {
         do {
             #if os(iOS)
             if micEnabled {
-                // .defaultToSpeaker: .playAndRecord otherwise routes to the iPhone EARPIECE; only
-                // affects the built-in route (headphones/BT still win).
+                // NO .defaultToSpeaker here, deliberately. It reads like "prefer the speaker over
+                // the earpiece", and the comment that used to sit here claimed headphones and
+                // Bluetooth still won. That is true of WIRED headphones and false of Bluetooth —
+                // a cable is the one way to test this and see the right answer. It is an
+                // OVERRIDE, and it outranks an A2DP route: with it set, every Bluetooth headset
+                // lost the stream to the phone's own speaker. That is the 0.25 field report ("no
+                // audio over Bluetooth ... plays through speakers if Mic input is enabled") — mic
+                // and echo cancellation both default to ON, so this branch is the DEFAULT path
+                // and every Bluetooth listener hit it; turning the mic off was the accidental
+                // workaround, because that lands on `.playback` below, which routes to A2DP
+                // happily.
+                //
+                // The earpiece problem it was reaching for is real, so it is solved after
+                // activation instead, against the route we were ACTUALLY given —
+                // see `steerBuiltInOutputToSpeaker`.
+                //
+                // `.allowBluetoothA2DP` alone, also deliberately: adding `.allowBluetooth` would
+                // make a headset's MIC usable, but it buys that by dragging the whole route onto
+                // HFP/SCO and collapsing game audio to narrowband. High-quality A2DP output plus
+                // the built-in mic is the better trade for a game-streaming client.
                 try session.setCategory(
                     .playAndRecord, mode: .default,
-                    options: [.allowBluetoothA2DP, .defaultToSpeaker])
+                    options: [.allowBluetoothA2DP])
                 // Uplink latency: ask for 5 ms IO quanta at the wire rate (the default ~10-23 ms
                 // quantum is most of the mic path's burst latency). Best-effort — the hardware
                 // has the final word (a Bluetooth route will ignore both), and whatever quantum
@@ -156,12 +186,66 @@ public final class SessionAudio {
             try session.setCategory(.playback, mode: .default)
             #endif
             try session.setActive(true)
+            #if os(iOS)
+            // Only the `.playAndRecord` session can land on the earpiece, and only it accepts an
+            // output override — so the mic-off (`.playback`) path deliberately does neither.
+            if micEnabled {
+                steerBuiltInOutputToSpeaker(session)
+                installRouteObserver()
+            }
+            #endif
         } catch {
             log.warning("AVAudioSession setup failed: \(error.localizedDescription)")
         }
     }
     #endif
 
+    #if os(iOS)
+    /// `.playAndRecord` parks the BUILT-IN output on the earpiece — right for a phone call,
+    /// useless for a game. Move it to the speaker, but ONLY when the route we were actually given
+    /// is the receiver: anything external (Bluetooth, wired, CarPlay, AirPlay) is left strictly
+    /// alone. That "look first" is the whole difference between this and the `.defaultToSpeaker`
+    /// option it replaced, which forced the speaker unconditionally and so beat Bluetooth.
+    ///
+    /// Idempotent and cheap, so the route observer can simply call it again.
+    private func steerBuiltInOutputToSpeaker(_ session: AVAudioSession) {
+        // An override already in force shows up as `.builtInSpeaker`, not `.builtInReceiver`, so
+        // re-running this never fights its own previous result.
+        guard session.currentRoute.outputs.contains(where: { $0.portType == .builtInReceiver })
+        else { return }
+        do {
+            try session.overrideOutputAudioPort(.speaker)
+        } catch {
+            log.warning("could not move audio off the earpiece: \(error.localizedDescription)")
+        }
+    }
+
+    /// Routes change under a live session: a headset connects mid-stream, or disconnects and hands
+    /// the stream back to the built-in output. iOS drops an output override whenever the route
+    /// changes — which is what lets a newly-connected headset win — so the earpiece steer is a
+    /// property of the CURRENT route and has to be re-applied per route. Without this, dropping
+    /// Bluetooth mid-stream would land the game on the earpiece.
+    private func installRouteObserver() {
+        let observer = NotificationCenter.default.addObserver(
+            forName: AVAudioSession.routeChangeNotification,
+            object: AVAudioSession.sharedInstance(), queue: nil
+        ) { [weak self] _ in
+            // Arrives on whatever thread AVFoundation posts it from, and the session API blocks
+            // on the audio server — so do the work on the shared session queue, like every
+            // other call into it.
+            SessionAudio.sessionQueue.async {
+                guard let self, !self.flag.isStopped else { return }
+                self.steerBuiltInOutputToSpeaker(AVAudioSession.sharedInstance())
+            }
+        }
+        stateLock.lock()
+        let stale = routeObserver
+        routeObserver = observer
+        stateLock.unlock()
+        if let stale { NotificationCenter.default.removeObserver(stale) }
+    }
+    #endif
+
     /// Build + start the engines — combined (voice-processed) or split, per `wantsCombined` —
     /// with the mic uplink only when enabled + authorized. Main thread (engine setup); on
     /// iOS/tvOS the session is already active by the time this runs.
@@ -249,7 +333,16 @@ public final class SessionAudio {
         combinedEngine = nil
         let wasDraining = drainStarted
         drainStarted = false
+        #if os(iOS)
+        let route = routeObserver
+        routeObserver = nil
+        #endif
         stateLock.unlock()
+        #if os(iOS)
+        // Before the deactivate below, so a route change during teardown can't re-steer a session
+        // we are in the middle of releasing.
+        if let route { NotificationCenter.default.removeObserver(route) }
+        #endif
         if let capture {
             capture.inputNode.removeTap(onBus: 0)
             capture.stop()

clients/apple/Sources/PunktfunkKit/Gamepad/GamepadCapture.swift

@@ -112,6 +112,24 @@ public final class GamepadCapture {
     static let escapeChordElements = [
         GCInputLeftShoulder, GCInputRightShoulder, GCInputButtonMenu, GCInputButtonOptions,
     ]
+    /// The stats-overlay chord: Select + X, one tier per completion (off → compact → normal →
+    /// detailed → off). It exists because a controller in both hands has no other way to the
+    /// numbers — the ⌃⌥⇧S combo needs a keyboard and the three-finger tap needs a free screen —
+    /// and on tvOS there is no other way AT ALL, which is what this fixes.
+    ///
+    /// Built like Android's mic chord (`GamepadRouter.MIC_CHORD`, Select + Y) and deliberately
+    /// not overlapping `escapeChord`: X is none of its four buttons, so no way of reaching the
+    /// exit chord passes through this one on the way, and vice versa. Select is a menu button
+    /// rather than a twitch action, which keeps the pair out of real play. Y is left free so the
+    /// mic chord can be ported onto it later without moving this one.
+    static let statsChord: UInt32 = GamepadWire.back | GamepadWire.x
+    /// `statsChord`'s elements by GameController alias — same mirror-the-mask rule (and same
+    /// invisible failure) as `escapeChordElements`; the same test pins both.
+    static let statsChordElements = [GCInputButtonOptions, GCInputButtonX]
+    /// Every element some chord reads — what a NON-forwarding slot claims (see `openSlot`). The
+    /// escape chord's four plus the stats chord's X; Select is shared, so it appears once.
+    static let chordElements: [String] =
+        escapeChordElements + statsChordElements.filter { !escapeChordElements.contains($0) }
     /// pf-client-core's `DISCONNECT_HOLD` — the same 1.5 s on every client.
     private static let disconnectHold: TimeInterval = 1.5
     /// pf-client-core's `GUIDE_HOLD`: hold Select alone this long → the HOST's guide goes
@@ -288,14 +306,15 @@ public final class GamepadCapture {
         // the PS button must open the host's Steam overlay. Restored to .enabled on close.
         //
         // With forwarding OFF none of that applies — no press reaches the host, so taking the
-        // user's screenshot gesture away buys nothing. NARROWED, not skipped: the escape chord
-        // is still read off this slot, and on tvOS it is the only controller way out of a
-        // stream, so the chord's own four elements keep their claim. (Menu especially: leave
-        // its gesture attached on tvOS and the press is the system's — the chord would never
-        // complete and the session would have no controller exit at all.)
+        // user's screenshot gesture away buys nothing. NARROWED, not skipped: the CHORDS are
+        // still read off this slot — on tvOS the escape chord is the only controller way out of
+        // a stream, and the stats chord the only way to the overlay — so their own elements keep
+        // their claim. (Menu especially: leave its gesture attached on tvOS and the press is the
+        // system's — the chord would never complete and the session would have no controller
+        // exit at all.)
         let claimed = forwarding
             ? Array(c.physicalInputProfile.elements.values)
-            : Self.escapeChordElements.compactMap { c.physicalInputProfile.elements[$0] }
+            : Self.chordElements.compactMap { c.physicalInputProfile.elements[$0] }
         for element in claimed {
             element.preferredSystemGestureState = .disabled
         }
@@ -437,10 +456,24 @@ public final class GamepadCapture {
         let newButtons = raw | (slot.buttons & GamepadWire.guide)
         let changed = newButtons ^ slot.buttons
         if changed != 0 {
+            let was = slot.buttons
             for bit in GamepadWire.allButtons where changed & bit != 0 {
                 wire?.send(.gamepadButton(bit, down: newButtons & bit != 0, pad: slot.pad))
             }
             slot.buttons = newButtons
+            // The stats chord, edge-triggered on the press that COMPLETES it: one cycle per
+            // chord rather than one per press, since a third button pressed on top finds the
+            // mask already complete and can't re-fire it. Read off the wire mask like the escape
+            // chord, which means a Select the hold-Select gesture has turned into a guide is not
+            // in it — a guide hold can't cycle the overlay on its way past. The buttons still
+            // forward (the chord is a local overlay change, not an input the host must not see).
+            if was & Self.statsChord != Self.statsChord,
+               newButtons & Self.statsChord == Self.statsChord {
+                // Straight to the shared tier default, like TouchMouse's three-finger tap: every
+                // reader (the HUD, the Settings pickers, the live session) observes it through
+                // @AppStorage, so no wiring back to the app is needed.
+                StatsVerbosity.cycle()
+            }
         }
         let newAxes: [Int32] = [
             Int32(g.leftThumbstick.xAxis.value * 32767),

clients/apple/Sources/PunktfunkKit/Gamepad/GamepadUIEnvironment.swift

@@ -3,20 +3,40 @@
 // layouts). A pure function, not a singleton: the reactivity comes from callers already observing
 // `GamepadManager.shared` and the `DefaultsKey.gamepadUIEnabled` @AppStorage themselves (the same
 // local-read pattern SettingsView already uses for GamepadManager), so this stays the single place
-// the two combine without adding a second ObservableObject or an environment key nobody else needs.
+// the inputs combine without adding a second ObservableObject or an environment key nobody else needs.
 
 import Foundation
 import PunktfunkShared
 
 public enum GamepadUIEnvironment {
-    /// `enabledSetting` is the user's Settings toggle (`DefaultsKey.gamepadUIEnabled`);
+    /// `DefaultsKey.gamepadUIMode`: take over only while a controller is attached. The default,
+    /// and what the switch meant when it was a lone Bool.
+    public static let modeWhenConnected = "connected"
+    /// `DefaultsKey.gamepadUIMode`: take over whenever the switch is on, pad or no pad — asked
+    /// for by people driving a TV-connected iPad or a couch Mac, where the console layout is the
+    /// one they want and the pad is not always awake.
+    public static let modeAlways = "always"
+
+    /// `enabledSetting` is the user's Settings switch (`DefaultsKey.gamepadUIEnabled`) — off means
+    /// the touch/desktop UI, full stop. `mode` is `DefaultsKey.gamepadUIMode`, and only matters
+    /// once the switch is on: `modeAlways` takes over unconditionally, anything else (including a
+    /// value a newer client wrote) waits for a controller.
+    ///
     /// `gamepadConnected` is `GamepadManager.shared.active != nil` — active only once a usable
     /// controller is actually attached (a non-extended-profile device leaves `active` nil, which
-    /// keeps the touch UI). A `Bool` rather than the `DiscoveredController` itself: this function's
-    /// whole job is the AND, so there's nothing else to inspect, and it keeps the helper testable
-    /// without a real `GCController` (which XCTest can't construct).
-    public static func isActive(gamepadConnected: Bool, enabledSetting: Bool) -> Bool {
-        enabledSetting && (gamepadConnected || forced)
+    /// keeps the touch UI). A `Bool` rather than the `DiscoveredController` itself: this function
+    /// has nothing else to inspect, and it keeps the helper testable without a real `GCController`
+    /// (which XCTest can't construct).
+    /// `mode` carries no default on purpose: a call site that forgot it would silently strand
+    /// everyone who picked Always back on "only with a controller", which is exactly the bug
+    /// this parameter exists to make impossible.
+    public static func isActive(
+        gamepadConnected: Bool,
+        enabledSetting: Bool,
+        mode: String
+    ) -> Bool {
+        guard enabledSetting else { return false }
+        return mode == modeAlways || gamepadConnected || forced
     }
 
     /// Dev-only escape hatch (like ContentView's `PUNKTFUNK_AUTOCONNECT`): pretend a controller is

clients/apple/Sources/PunktfunkKit/Input/SiriRemotePointer.swift

@@ -34,10 +34,26 @@ public final class SiriRemotePointer {
     private var heldButtons: Set<UInt32> = []
     /// When Back/Menu went down; a release after `disconnectHold` fires the exit.
     private var menuDownAt: Date?
+    /// Counts a held Play/Pause down to `statsHold`; nil when the button is up or already
+    /// resolved. See `playPauseChanged`.
+    private var playPauseTimer: Timer?
+    /// The held Play/Pause has already been spent on a stats cycle, so its release must not also
+    /// right-click.
+    private var statsHoldFired = false
+    /// Trails a delivered right-click tap by `tapPress` to release it — see `deliverRightClick`.
+    private var rightReleaseTimer: Timer?
 
     /// Hold Back/Menu at least this long (then release) to end the session. Shorter than the
     /// controller chord's 1.5 s — the remote has no way to trip this during gameplay.
     private static let disconnectHold: TimeInterval = 1.0
+    /// Hold Play/Pause this long to cycle the stats overlay instead of right-clicking. It is the
+    /// remote's only spare button, and on an Apple TV with no controller in the room this is the
+    /// ONLY route to the numbers (⌃⌥⇧S wants a keyboard, the three-finger tap a touchscreen).
+    /// Shorter than `disconnectHold`: nothing destructive rides on it.
+    private static let statsHold: TimeInterval = 0.5
+    /// pf-client-core's `TAP_PRESS`, borrowed for the deferred right-click: its release trails
+    /// the press by this much, so the two transitions can't fold into nothing downstream.
+    private static let tapPress: TimeInterval = 0.05
     /// A full edge-to-edge swipe moves the host cursor about this many pixels. The surface is
     /// small; two comfortable swipes should cross a 1080p desktop.
     private static let pointerScale: Float = 1100
@@ -95,6 +111,9 @@ public final class SiriRemotePointer {
             old.buttonX.pressedChangedHandler = nil
             old.buttonMenu.pressedChangedHandler = nil
         }
+        // Timers first, then the lift: a tap whose release is still owed is held state, so
+        // `releaseHeld` below is what sends its button-up.
+        cancelPlayPause()
         releaseHeld()
         lastTouch = nil
         menuDownAt = nil
@@ -109,12 +128,13 @@ public final class SiriRemotePointer {
         micro.dpad.valueChangedHandler = { [weak self] _, x, y in
             MainActor.assumeIsolated { self?.touchMoved(x: x, y: y) }
         }
-        // Surface click = left button; Play/Pause = right (the remote's only spare face button).
+        // Surface click = left button; Play/Pause = right (the remote's only spare face button),
+        // or — held — the stats-overlay cycle. See `playPauseChanged`.
         micro.buttonA.pressedChangedHandler = { [weak self] _, _, pressed in
             MainActor.assumeIsolated { self?.setButton(1, down: pressed) }
         }
         micro.buttonX.pressedChangedHandler = { [weak self] _, _, pressed in
-            MainActor.assumeIsolated { self?.setButton(3, down: pressed) }
+            MainActor.assumeIsolated { self?.playPauseChanged(pressed: pressed) }
         }
         micro.buttonMenu.pressedChangedHandler = { [weak self] _, _, pressed in
             MainActor.assumeIsolated { self?.menuChanged(pressed: pressed) }
@@ -149,6 +169,76 @@ public final class SiriRemotePointer {
         connection.send(.mouseButton(button, down: down))
     }
 
+    /// Play/Pause: a TAP right-clicks, a HOLD (`statsHold`) cycles the stats overlay instead.
+    ///
+    /// The right button is therefore DEFERRED until the press resolves, rather than going down on
+    /// contact: once the host has seen a button-down there is no taking it back, and a right
+    /// button held for half a second is a context menu on every desktop this streams. The shape
+    /// is the hold-Select gesture's (`GamepadCapture.gestureFiltered`) — suppress, then deliver a
+    /// tap on release or the gesture past the threshold — so the two behave alike.
+    private func playPauseChanged(pressed: Bool) {
+        if pressed {
+            statsHoldFired = false
+            let timer = Timer(timeInterval: Self.statsHold, repeats: false) { [weak self] _ in
+                Task { @MainActor in self?.statsHoldElapsed() }
+            }
+            RunLoop.main.add(timer, forMode: .common)
+            playPauseTimer?.invalidate()
+            playPauseTimer = timer
+            return
+        }
+        playPauseTimer?.invalidate()
+        playPauseTimer = nil
+        // The hold already spent this press on a cycle — its release clicks nothing.
+        guard !statsHoldFired else {
+            statsHoldFired = false
+            return
+        }
+        deliverRightClick()
+    }
+
+    /// The threshold passed with Play/Pause still down → cycle the overlay and consume the press.
+    /// Writes the shared `statsVerbosity` default every reader observes through @AppStorage — the
+    /// same cycle as ⌃⌥⇧S, the three-finger tap and the controller's Select + X.
+    private func statsHoldElapsed() {
+        playPauseTimer = nil
+        statsHoldFired = true
+        StatsVerbosity.cycle()
+    }
+
+    /// A Play/Pause tap, delivered now that it resolved as one: the right button down, its
+    /// release `tapPress` behind so the pair can't collapse into nothing downstream.
+    private func deliverRightClick() {
+        // A previous tap's owed release goes out FIRST — two taps inside `tapPress` would
+        // otherwise send the host two downs in a row (the rule GamepadCapture's held-back Select
+        // tap follows for the same reason).
+        finishRightClick()
+        setButton(3, down: true)
+        let timer = Timer(timeInterval: Self.tapPress, repeats: false) { [weak self] _ in
+            Task { @MainActor in self?.finishRightClick() }
+        }
+        RunLoop.main.add(timer, forMode: .common)
+        rightReleaseTimer = timer
+    }
+
+    /// Release a tap's right button if one is still owed; nothing otherwise.
+    private func finishRightClick() {
+        guard rightReleaseTimer != nil else { return }
+        rightReleaseTimer?.invalidate()
+        rightReleaseTimer = nil
+        setButton(3, down: false)
+    }
+
+    /// Drop any in-flight Play/Pause state (unbind / stop). Timers only — a right button already
+    /// sent down is held state, and `releaseHeld` is what lifts it.
+    private func cancelPlayPause() {
+        playPauseTimer?.invalidate()
+        playPauseTimer = nil
+        rightReleaseTimer?.invalidate()
+        rightReleaseTimer = nil
+        statsHoldFired = false
+    }
+
     private func menuChanged(pressed: Bool) {
         if pressed {
             menuDownAt = Date()

clients/apple/Sources/PunktfunkShared/DefaultsKeys.swift

@@ -176,16 +176,23 @@ public enum DefaultsKey {
     /// ("topLeading"/"topTrailing"/"bottomLeading"/"bottomTrailing"). Default top-trailing.
     public static let hudPlacement = "punktfunk.hudPlacement"
     /// iOS/iPadOS/macOS: switch the host list, settings and game library to a controller-friendly
-    /// layout (the console launcher, gamepad-navigable settings, a coverflow-style library)
-    /// whenever a gamepad is connected. On by default; see `GamepadUIEnvironment.isActive`.
+    /// layout (the console launcher, gamepad-navigable settings, a coverflow-style library).
+    /// On by default; WHEN it takes over is `gamepadUIMode`. See `GamepadUIEnvironment.isActive`.
     public static let gamepadUIEnabled = "punktfunk.gamepadUIEnabled"
+    /// When `gamepadUIEnabled` actually takes over: `"connected"` (the default — only while a
+    /// usable controller is attached, the behaviour this switch has always had) or `"always"`,
+    /// for someone who prefers the console layout with no pad in reach (a TV-connected iPad, a
+    /// Mac driven from the couch). Read only while `gamepadUIEnabled` is on, which is why the
+    /// settings rows hide it when the switch is off. Anything unrecognized reads as
+    /// `"connected"`. A device preference, never part of a stream profile.
+    public static let gamepadUIMode = "punktfunk.gamepadUIMode"
     /// Which colour family the gamepad UI's living backdrop drifts through — a
-    /// `GamepadPalette` id ("violet" = the brand default, then "tide"/"forest"/"ember"/
-    /// "rose"/"graphite"). The cross-client `ui_palette` key: the desktop console and the
-    /// Android client carry the same table under the same names. Presentation only, so it is
-    /// a device preference and never part of a stream profile. An unknown value reads as the
-    /// default rather than failing — a newer client may have shipped a palette this build
-    /// doesn't know.
+    /// `GamepadPalette` id ("violet" = the brand default, then "oled"/"nebula"/"abyss"/"ember"/
+    /// "moss"/"graphite", then the pale ones). The cross-client `ui_palette` key: the desktop
+    /// console and the Android client carry the same table under the same names. Presentation
+    /// only, so it is a device preference and never part of a stream profile. An unknown value
+    /// reads as the default rather than failing — a newer client may have shipped a palette this
+    /// build doesn't know.
     public static let uiPalette = "punktfunk.uiPalette"
     /// iPhone: ALSO play the rumble the host addresses to controller 1 (wire pad 0) on this
     /// device's own Taptic Engine — for phone-clip pads that ship without rumble motors, where

clients/apple/Sources/PunktfunkShared/GamepadPalette.swift

@@ -65,13 +65,25 @@ public struct GamepadPalette: Identifiable, Equatable, Sendable {
         SIMD3(0.22, 0.38, 0.86), SIMD3(0.53, 0.47, 0.96),
     ]
 
-    /// The twelve shipped palettes: the brand default, five more dark fields, then six pale
+    /// The thirteen shipped palettes: the brand default, six more dark fields, then six pale
     /// ones. Cycling order runs dark → light, so stepping the row walks the whole range one way.
     public static let all: [GamepadPalette] = [
         // --- dark fields (white ink) ---
         GamepadPalette(
             id: "violet", name: "Violet", stops: [],
             ground: SIMD3(0.075, 0.060, 0.160), accent: SIMD3(0.525, 0.471, 0.961), light: false),
+        GamepadPalette(
+            // For OLED and AMOLED panels, where a black pixel is a pixel switched off — no glow,
+            // no power. The first two stops are literally (0,0,0), so the shaded half of the
+            // field is genuinely off rather than "very dark grey", and the ground is pure black
+            // too: the calm mix on the form screens lifts toward nothing. What is left is a
+            // faint indigo→violet ember in the bright corner. The accent stays the brand violet
+            // — focus has to be findable on black.
+            id: "oled", name: "OLED",
+            stops: [SIMD3(0.000, 0.000, 0.000), SIMD3(0.000, 0.000, 0.000),
+                    SIMD3(0.010, 0.020, 0.100), SIMD3(0.045, 0.016, 0.115),
+                    SIMD3(0.120, 0.024, 0.130)],
+            ground: SIMD3(0, 0, 0), accent: SIMD3(0.525, 0.471, 0.961), light: false),
         GamepadPalette(
             // Deep indigo climbing through violet into a hot magenta.
             id: "nebula", name: "Nebula",

clients/apple/Tests/PunktfunkKitTests/AudioRingDriftTests.swift

@@ -53,11 +53,22 @@ final class AudioRingDriftTests: XCTestCase {
         XCTAssertEqual(silent, 0, "drift correction must never starve the callback")
     }
 
-    /// The mirror case: a host clock running SLOW must keep audio flowing rather than being
-    /// "corrected" into a stutter.
-    func testNegativeDriftKeepsPlaying() {
+    /// The mirror case: a host clock running SLOW is a genuine deficit — no depth is ever deep
+    /// enough forever — so the ring must spend it on RARE, clean re-banks (a hollow ring
+    /// re-primes on its first click and refills the whole target) rather than riding the knife
+    /// edge in permanent sub-frame chatter, which is what "silence-free" used to hide: every
+    /// callback a fraction of a frame short, none of them fully silent, all of them audible.
+    /// −200 ppm is an exaggeration of real DAC skew (tens of ppm); even so, two minutes may
+    /// cost at most a couple of refills' worth of silent callbacks.
+    func testNegativeDriftBanksRarelyInsteadOfChattering() {
         let (_, _, silent) = simulate(ms: 2 * 60 * 1_000, quantumMS: 5, driftPPM: -200)
-        XCTAssertEqual(silent, 0, "a draining ring must re-prime, not chatter")
+        XCTAssertLessThanOrEqual(
+            silent, 24,
+            "a draining ring re-banks a few times; a silent-callback stream means it is thrashing")
+        XCTAssertGreaterThan(
+            silent, 0,
+            "a persistent deficit cannot be ridden out silence-free — if this is zero the ring "
+                + "is back to sub-frame chatter, which is audible without ever being silent")
     }
 
     /// A device that pulls a large quantum cannot sustain a target below it — the ring must lift
@@ -79,11 +90,14 @@ final class AudioRingDriftTests: XCTestCase {
         scratch.withUnsafeMutableBufferPointer { ring.read(into: $0.baseAddress!, count: want) }
         XCTAssertTrue(scratch.contains { $0 != 0 }, "should be playing after priming")
 
-        // Drain it dry with one oversized read, then feed a normal quantum again. The length comes
-        // off the buffer pointer, not off `huge`: touching the array inside the closure that is
-        // already holding it exclusively is an exclusivity violation.
-        var huge = [Float](repeating: 0, count: 200 * perMS)
-        huge.withUnsafeMutableBufferPointer { ring.read(into: $0.baseAddress!, count: $0.count) }
+        // Drain it dry at the device's own quantum — an oversized read would count as ITS OWN
+        // huge callback and legitimately read as hollow — then starve one callback and feed a
+        // normal quantum again. The ring is freshly primed, so its depth average is nowhere near
+        // hollow, and one short read must ride on the hysteresis.
+        while ring.bufferedMS > 0 {
+            scratch.withUnsafeMutableBufferPointer { ring.read(into: $0.baseAddress!, count: want) }
+        }
+        scratch.withUnsafeMutableBufferPointer { ring.read(into: $0.baseAddress!, count: want) }
         let feed = [Float](repeating: 0.5, count: want)
         feed.withUnsafeBufferPointer { ring.write($0.baseAddress!, count: want) }
         scratch.withUnsafeMutableBufferPointer { ring.read(into: $0.baseAddress!, count: want) }
@@ -92,14 +106,17 @@ final class AudioRingDriftTests: XCTestCase {
             "a single short read must not force a full re-prime")
     }
 
-    /// Mirror of the Rust `target_grows_on_underruns_and_relaxes_when_quiet`: clustered genuine
-    /// underruns raise the target floor (that session needs the slack), a long quiet spell gives
-    /// it back — and the floor never dips below the base.
+    /// Mirror of the Rust `target_grows_on_underruns_and_relaxes_when_quiet`, updated for
+    /// near-miss growth: the drain's LAST full read (less than a frame left over) already grows
+    /// the floor before anything was audible, clustered genuine underruns raise it further, and
+    /// a long — genuinely quiet — spell gives it back, never below the base. The quiet refill
+    /// runs DEEP: a knife-edge refill (exactly what each read takes) leaves the ring within a
+    /// frame of empty every callback, which now correctly reads as pressure, not quiet.
     func testTargetGrowsOnUnderrunsAndRelaxesWhenQuiet() {
         let ring = AudioRing(capacity: 48_000 * channels, channels: channels)
         let want = 5 * perMS
         var scratch = [Float](repeating: 0, count: want)
-        let feed = [Float](repeating: 0.5, count: 25 * perMS)
+        let feed = [Float](repeating: 0.5, count: 60 * perMS)
         func write(ms: Int) {
             feed.withUnsafeBufferPointer { ring.write($0.baseAddress!, count: ms * perMS) }
         }
@@ -108,20 +125,27 @@ final class AudioRingDriftTests: XCTestCase {
         }
         XCTAssertEqual(ring.stats.targetMS, 20, "base target must match JitterTuning.COREAUDIO")
 
-        // Prime, drain dry, then alternate starve/refill: each dry read is a genuine underrun,
-        // each full read in between keeps the de-prime hysteresis from tripping.
+        // Prime, then drain: the 5th read is still served in full but leaves nothing over — a
+        // near-miss, and the floor grows BEFORE any click.
         write(ms: 25)
-        for _ in 0..<5 { read() } // drains to zero
+        for _ in 0..<5 { read() }
+        XCTAssertEqual(ring.stats.targetMS, 30, "a near-miss must grow the floor pre-click")
+        XCTAssertEqual(ring.stats.underruns, 0, "nothing was audible yet")
+
+        // Then alternate starve/refill: each dry read is a genuine underrun, each full read in
+        // between keeps the de-prime hysteresis from tripping. (The refills land as further
+        // near-misses, but growth is one step per window — the cluster is what grows it again.)
         read() // short — underrun 1
         write(ms: 5); read() // full — hysteresis reset
         read() // short — underrun 2
         write(ms: 5); read() // full
         read() // short — underrun 3 → the floor grows one step
-        XCTAssertEqual(ring.stats.targetMS, 30, "3 clustered underruns must grow the target 10 ms")
+        XCTAssertEqual(ring.stats.targetMS, 40, "3 clustered underruns must grow the target 10 ms")
         XCTAssertEqual(ring.stats.underruns, 3)
 
-        // A long clean run (30 s of consumed audio) relaxes the growth back to the base…
-        for _ in 0..<(30_000 / 5 + 10) {
+        // A long clean run at a healthy depth relaxes the growth back to the base…
+        write(ms: 60)
+        for _ in 0..<(90_000 / 5 + 10) {
             write(ms: 5)
             read()
         }
@@ -435,10 +459,14 @@ final class AudioRingDriftTests: XCTestCase {
             write(ms: 5); read()
             read()
         }
-        /// Quiet (full) reads needed before the grown target relaxes one step.
+        /// Quiet (full) reads needed before the grown target relaxes one step. The ring is
+        /// refilled DEEP first: a knife-edge refill (exactly what each read takes) leaves less
+        /// than a frame over every callback, which now correctly reads as pressure — near-misses
+        /// — and pressure never relaxes anything.
         func quietToRelax(_ ring: AudioRing) -> Int {
             var scratch = [Float](repeating: 0, count: want)
-            let feed = [Float](repeating: 0.5, count: 5 * perMS)
+            let feed = [Float](repeating: 0.5, count: 60 * perMS)
+            feed.withUnsafeBufferPointer { ring.write($0.baseAddress!, count: 60 * perMS) }
             let start = ring.stats.targetMS
             var reads = 0
             while ring.stats.targetMS == start, reads < 200_000 {
@@ -466,6 +494,118 @@ final class AudioRingDriftTests: XCTestCase {
             "sync pressure should relax sooner: \(fastReads) vs \(slowReads) quiet reads")
     }
 
+    /// A shrink answered by an underrun or near-miss inside its probe window is undone AT ONCE,
+    /// and the sync loop is backed off — mirrors the Rust `a_failed_shrink_probe_is_undone_at_once`
+    /// and `a_failed_probe_backs_the_sync_shrink_off`. Before this, the loop re-probed a proven
+    /// depth every five quiet seconds and paid an audible starvation event each time it was wrong,
+    /// forever — the 0.25.0 MacBook field report.
+    func testAFailedShrinkProbeIsUndoneAtOnceAndBacksTheSyncLoopOff() {
+        let ring = AudioRing(capacity: 48_000 * channels, channels: channels)
+        let want = 5 * perMS
+        var scratch = [Float](repeating: 0, count: want)
+        let feed = [Float](repeating: 0.5, count: 60 * perMS)
+        func write(ms: Int) {
+            feed.withUnsafeBufferPointer { ring.write($0.baseAddress!, count: ms * perMS) }
+        }
+        func read() {
+            scratch.withUnsafeMutableBufferPointer { ring.read(into: $0.baseAddress!, count: want) }
+        }
+        // Grow the floor (near-miss + a cluster of genuine underruns), as the usual pattern does.
+        write(ms: 25)
+        for _ in 0..<5 { read() }
+        read()
+        write(ms: 5); read()
+        read()
+        write(ms: 5); read()
+        read()
+        let grown = ring.stats.targetMS
+        XCTAssertGreaterThan(grown, 20, "the test needs a GROWN floor to probe")
+
+        // Sync asks for less; a deep, genuinely quiet spell later the shrink probes.
+        ring.setSyncTarget(perMS)
+        write(ms: 60)
+        var reads = 0
+        while ring.stats.targetMS == grown, reads < 10_000 {
+            write(ms: 5)
+            read()
+            reads += 1
+        }
+        XCTAssertEqual(ring.stats.targetMS, grown - 10, "the sync-driven shrink must have probed")
+
+        // Drain to the knife edge: the last full read leaves nothing over — a near-miss, nobody
+        // heard anything — and the probe must be undone on the spot.
+        while ring.bufferedMS > 5 { read() }
+        read()
+        XCTAssertEqual(
+            ring.stats.targetMS, grown,
+            "a failed probe must restore the target on the first near-miss")
+        XCTAssertEqual(ring.stats.underruns, 3, "and nothing audible may have paid for it")
+
+        // Backed off: two accelerated windows of clean, deep audio must NOT shrink again…
+        write(ms: 60)
+        for _ in 0..<(2 * 5_000 / 5) {
+            write(ms: 5)
+            read()
+        }
+        XCTAssertEqual(
+            ring.stats.targetMS, grown,
+            "the five-second cadence must be suspended after a failure")
+        // …while the slow, pre-sync window eventually still tests one — backoff is not a freeze.
+        for _ in 0..<(2 * 30_000 / 5) {
+            write(ms: 5)
+            read()
+        }
+        XCTAssertLessThan(
+            ring.stats.targetMS, grown,
+            "the slow window must still be allowed to test a shrink")
+    }
+
+    /// Growth raises a promise; only a re-prime banks real depth. An underrun while the ring is
+    /// HOLLOW — its depth AVERAGE far below the target — re-primes immediately, spending the click
+    /// it already cost on the whole refill, instead of riding the knife edge and clicking once per
+    /// bunching period indefinitely. The average, not the instant, is what separates a hollow ring
+    /// from one late packet (`testSingleShortReadDoesNotDeprime` pins that side).
+    func testAHollowRingReprimesOnItsFirstClick() {
+        let ring = AudioRing(capacity: 48_000 * channels, channels: channels)
+        let want = 5 * perMS
+        var scratch = [Float](repeating: 0, count: want)
+        let feed = [Float](repeating: 0.5, count: 60 * perMS)
+        func write(ms: Int) {
+            feed.withUnsafeBufferPointer { ring.write($0.baseAddress!, count: ms * perMS) }
+        }
+        func read() {
+            scratch.withUnsafeMutableBufferPointer { ring.read(into: $0.baseAddress!, count: want) }
+        }
+        // Grow the floor to 40 the usual way…
+        write(ms: 25)
+        for _ in 0..<5 { read() }
+        read()
+        write(ms: 5); read()
+        read()
+        write(ms: 5); read()
+        read()
+        XCTAssertEqual(ring.stats.targetMS, 40)
+        // …then ride the knife edge for ~2 s of audio, so the depth average genuinely sinks far
+        // below the promised 40 ms.
+        for _ in 0..<400 {
+            write(ms: 5)
+            read()
+        }
+        // One dry read — the click. The ring is hollow, so this single click must re-prime.
+        read()
+        // A packet arrives, but the ring stays SILENT: it is re-priming toward the full target
+        // rather than playing the packet and clicking again at the next bunch.
+        write(ms: 10)
+        read()
+        XCTAssertTrue(
+            scratch.allSatisfy { $0 == 0 },
+            "a hollow ring must spend its click on the whole refill, not keep limping")
+        // And once the refill reaches the target, it plays again.
+        write(ms: 40)
+        read()
+        XCTAssertTrue(scratch.contains { $0 != 0 }, "refilled to target — playback resumes")
+    }
+
     /// The four client rings adopt sync one at a time; an un-wired one must behave exactly as it
     /// did. `nil` is the default, so this pins the initializer too — and every other test in this
     /// file runs without a sync target, which is the real guard that nothing moved underneath them.

clients/apple/Tests/PunktfunkKitTests/GamepadEscapeChordTests.swift

@@ -5,8 +5,9 @@ import XCTest
 
 /// The escape chord's mask and its GameController alias list have to describe the same four
 /// buttons. `GamepadCapture.openSlot` claims the system gesture of every element while forwarding
-/// is on, but only of `escapeChordElements` while it is off — so if the alias list ever stops
-/// covering the mask, the missing button's press stays the system's and the chord never completes.
+/// is on, but only of `chordElements` — `escapeChordElements` plus the stats chord's — while it is
+/// off, so if this alias list ever stops covering the mask, the missing button's press stays the
+/// system's and the chord never completes. (`GamepadStatsChordTests` pins the claim list itself.)
 ///
 /// That matters most on tvOS, where this chord is the only controller way out of a stream: the
 /// symptom is a session nobody can leave with the pad in their hands, and nothing logs or crashes.

clients/apple/Tests/PunktfunkKitTests/GamepadPaletteTests.swift

@@ -46,12 +46,29 @@ final class GamepadPaletteTests: XCTestCase {
     func testTableMatchesTheOtherClients() {
         XCTAssertEqual(
             GamepadPalette.all.map(\.id),
-            ["violet", "nebula", "abyss", "ember", "moss", "graphite",
+            ["violet", "oled", "nebula", "abyss", "ember", "moss", "graphite",
              "holo", "sunset", "bloom", "dawn", "mint", "opal"])
         // Dark fields lead, pale ones follow, so stepping the row walks one direction.
         let firstLight = GamepadPalette.all.firstIndex { $0.light }
-        XCTAssertEqual(firstLight, 6)
-        XCTAssertTrue(GamepadPalette.all.dropFirst(6).allSatisfy(\.light))
+        XCTAssertEqual(firstLight, 7)
+        XCTAssertTrue(GamepadPalette.all.dropFirst(7).allSatisfy(\.light))
+    }
+
+    /// OLED is the one palette whose selling point is measurable: it has to be genuinely black,
+    /// not merely the darkest of the dark fields.
+    func testOLEDIsActuallyBlack() {
+        let oled = GamepadPalette.named("oled")
+        XCTAssertEqual(oled.ground, SIMD3(0, 0, 0), "the calm lift must be nothing")
+        let cells = oled.meshColors
+        XCTAssertGreaterThanOrEqual(
+            cells.filter { luma($0) == 0 }.count, 3,
+            "the shaded corner has to be switched off, not dimmed")
+        let mean = cells.map(luma).reduce(0, +) / Double(cells.count)
+        let darkestOther = GamepadPalette.all
+            .filter { $0.id != "oled" }
+            .map { p in p.meshColors.map(luma).reduce(0, +) / Double(p.meshColors.count) }
+            .min() ?? 0
+        XCTAssertLessThan(mean, darkestOther / 2, "oled is barely darker than \(darkestOther)")
     }
 
     /// A palette must read as SEVERAL hues, not one hue at several brightnesses — that was

clients/apple/Tests/PunktfunkKitTests/GamepadStatsChordTests.swift

@@ -0,0 +1,79 @@
+import GameController
+import XCTest
+
+@testable import PunktfunkKit
+
+/// The stats chord (Select + X) has the same drift hazard as the escape chord it sits beside: its
+/// mask and its GameController alias list must describe the same buttons, and every element some
+/// chord reads has to appear in the list a NON-forwarding slot claims — otherwise that button's
+/// press stays the system's and the chord silently never completes.
+///
+/// It matters most on tvOS, where this is the only way to the statistics overlay at all (no
+/// keyboard for ⌃⌥⇧S, no touchscreen for the three-finger tap). The failure looks like nothing
+/// happening, so it is pinned here rather than left to the comments.
+@MainActor
+final class GamepadStatsChordTests: XCTestCase {
+
+    /// The intended alias↔bit pairing, spelled out independently of the implementation.
+    private let pairing: [(alias: String, bit: UInt32)] = [
+        (GCInputButtonOptions, GamepadWire.back),
+        (GCInputButtonX, GamepadWire.x),
+    ]
+
+    func testChordMaskIsExactlyTheTwoPairedButtons() {
+        XCTAssertEqual(
+            pairing.reduce(UInt32(0)) { $0 | $1.bit },
+            GamepadCapture.statsChord,
+            "the chord mask and the alias pairing describe different buttons")
+    }
+
+    func testAliasListMirrorsTheMask() {
+        XCTAssertEqual(
+            GamepadCapture.statsChordElements.count,
+            GamepadCapture.statsChord.nonzeroBitCount,
+            "alias list and chord mask differ in size")
+        XCTAssertEqual(GamepadCapture.statsChordElements, pairing.map(\.alias))
+    }
+
+    /// The two chords must not be reachable through one another: pressing toward the exit chord
+    /// may not cycle the overlay on the way, and holding the stats chord may not arm a disconnect.
+    /// Select is the one button they share by design — everything else has to be disjoint.
+    func testChordsOverlapOnlyOnSelect() {
+        XCTAssertEqual(
+            GamepadCapture.statsChord & GamepadCapture.escapeChord,
+            GamepadWire.back,
+            "the stats and escape chords share a button other than Select")
+        // Neither is a subset of the other, so completing one can never complete the other.
+        XCTAssertNotEqual(
+            GamepadCapture.statsChord & GamepadCapture.escapeChord, GamepadCapture.statsChord)
+        XCTAssertNotEqual(
+            GamepadCapture.statsChord & GamepadCapture.escapeChord, GamepadCapture.escapeChord)
+    }
+
+    /// `chordElements` is what `openSlot` claims when forwarding is OFF. It must cover BOTH
+    /// chords' aliases and repeat none of them (a duplicate would mean a bit with no element).
+    func testClaimListCoversBothChordsWithoutDuplicates() {
+        let claim = GamepadCapture.chordElements
+        for alias in GamepadCapture.escapeChordElements + GamepadCapture.statsChordElements {
+            XCTAssertTrue(claim.contains(alias), "\(alias) is read by a chord but never claimed")
+        }
+        XCTAssertEqual(Set(claim).count, claim.count, "a repeated alias in the claim list")
+        // Shared Select means the union is one shorter than the two lists laid end to end.
+        XCTAssertEqual(
+            claim.count,
+            GamepadCapture.escapeChordElements.count + GamepadCapture.statsChordElements.count - 1)
+    }
+
+    /// A cycle is a pure rotation through the four tiers — the chord fires `StatsVerbosity.cycle`,
+    /// and a tier that dead-ended would strand a tvOS user with no other way back.
+    func testCycleReachesEveryTierAndReturns() {
+        var tier = StatsVerbosity.off
+        var seen: [StatsVerbosity] = []
+        for _ in 0..<StatsVerbosity.allCases.count {
+            seen.append(tier)
+            tier = tier.next()
+        }
+        XCTAssertEqual(Set(seen).count, StatsVerbosity.allCases.count, "a tier is unreachable")
+        XCTAssertEqual(tier, .off, "the cycle does not return to where it started")
+    }
+}

clients/apple/Tests/PunktfunkKitTests/GamepadUIEnvironmentTests.swift

@@ -1,14 +1,58 @@
-// GamepadUIEnvironment.isActive is a pure AND — table-tested exhaustively over its 2x2 inputs.
+// GamepadUIEnvironment.isActive is pure — table-tested exhaustively over its inputs.
 
 import XCTest
 
 @testable import PunktfunkKit
 
 final class GamepadUIEnvironmentTests: XCTestCase {
-    func testActiveOnlyWhenEnabledAndConnected() {
-        XCTAssertTrue(GamepadUIEnvironment.isActive(gamepadConnected: true, enabledSetting: true))
-        XCTAssertFalse(GamepadUIEnvironment.isActive(gamepadConnected: true, enabledSetting: false))
-        XCTAssertFalse(GamepadUIEnvironment.isActive(gamepadConnected: false, enabledSetting: true))
-        XCTAssertFalse(GamepadUIEnvironment.isActive(gamepadConnected: false, enabledSetting: false))
+    private let connected = GamepadUIEnvironment.modeWhenConnected
+    private let always = GamepadUIEnvironment.modeAlways
+
+    /// The default mode is the behaviour the switch had when it was a lone Bool, so an install
+    /// that never sees the new row is exactly where it was.
+    func testWhenConnectedIsAPlainAnd() {
+        XCTAssertTrue(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: true, enabledSetting: true, mode: connected))
+        XCTAssertFalse(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: true, enabledSetting: false, mode: connected))
+        XCTAssertFalse(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: false, enabledSetting: true, mode: connected))
+        XCTAssertFalse(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: false, enabledSetting: false, mode: connected))
+    }
+
+    /// Always drops the controller from the decision entirely — but NOT the switch, which stays
+    /// the one way back to the touch UI.
+    func testAlwaysIgnoresTheControllerButNotTheSwitch() {
+        XCTAssertTrue(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: false, enabledSetting: true, mode: always))
+        XCTAssertTrue(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: true, enabledSetting: true, mode: always))
+        XCTAssertFalse(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: false, enabledSetting: false, mode: always))
+        XCTAssertFalse(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: true, enabledSetting: false, mode: always))
+    }
+
+    /// A value a newer client wrote must wait for a controller, never strand this build in a
+    /// layout it has no way back out of.
+    func testUnknownModeWaitsForAController() {
+        XCTAssertFalse(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: false, enabledSetting: true, mode: "whenever-i-say-so"))
+        XCTAssertTrue(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: true, enabledSetting: true, mode: "whenever-i-say-so"))
+        XCTAssertFalse(
+            GamepadUIEnvironment.isActive(
+                gamepadConnected: false, enabledSetting: true, mode: ""))
     }
 }

clients/decky/main.py

@@ -303,6 +303,58 @@ def _native_client() -> str | None:
     return None
 
 
+# The one architecture the flatpak client is built for.
+_FLATPAK_ARCH = "x86_64"
+
+
+def _flatpak_ref() -> dict | None:
+    """The INSTALLED client flatpak resolved to a SCOPE and a BRANCH, or None when there is none.
+
+    ``{"scope": "--user"|"--system", "branch": "canary", "ref": "io.unom.Punktfunk//canary"}``.
+
+    ⭐⭐ **Naming no branch is not a shorthand for "the only one".** flatpak refuses an ambiguous
+    ref rather than guessing at one, and the ambiguity does not need two branches *installed*:
+    the punktfunk remote publishes `stable` AND `canary`, so an unqualified
+    ``flatpak remote-info <origin> io.unom.Punktfunk`` errors with "Multiple branches available"
+    on a Deck that has exactly one. That error is why the client update check silently answered
+    "up to date" on every Deck — so every query downstream now names the ref in full.
+
+    Read off the exported tree rather than by shelling out to ``flatpak list``, because
+    :func:`_client_argv` is on the path of every headless call and a subprocess per call would be
+    absurd (the same reason :func:`_flatpak_installed` reads the filesystem). ``active`` is the
+    symlink flatpak points at the deployed commit — its presence is what makes a branch directory
+    an INSTALL rather than the leftovers of one.
+
+    With more than one branch installed, `stable` wins, because that is the branch a plain
+    ``flatpak run`` resolves to: the check has to describe the client the launcher really starts,
+    or a stale `stable` silently beats a current `canary` in both places at once.
+    """
+    if not _flatpak():
+        return None
+    for root, scope in (
+        (Path(decky.DECKY_USER_HOME) / ".local" / "share" / "flatpak", "--user"),
+        (Path("/var/lib/flatpak"), "--system"),
+    ):
+        try:
+            branches = sorted(
+                p.name for p in (root / "app" / APP_ID / _FLATPAK_ARCH).iterdir()
+                if (p / "active").exists()
+            )
+        except OSError:
+            continue  # not installed in this scope
+        if not branches:
+            continue
+        branch = "stable" if "stable" in branches else branches[0]
+        if len(branches) > 1:
+            decky.logger.warning(
+                "%s is installed on %d branches (%s) — using %s, the one `flatpak run` resolves "
+                "to; uninstall the others so the client you launch is the client we update",
+                APP_ID, len(branches), ", ".join(branches), branch,
+            )
+        return {"scope": scope, "branch": branch, "ref": f"{APP_ID}//{branch}"}
+    return None
+
+
 def _flatpak_installed() -> bool:
     """True when the flatpak APP is actually installed — not merely that `flatpak` exists.
 
@@ -310,10 +362,7 @@ def _flatpak_installed() -> bool:
     because this is on the path of every headless call and a subprocess per call would be absurd.
     Both scopes count: the Deck installs --user, a distro image may ship it system-wide.
     """
-    if not _flatpak():
-        return False
-    user = Path(decky.DECKY_USER_HOME) / ".local" / "share" / "flatpak" / "app" / APP_ID
-    return user.exists() or Path("/var/lib/flatpak/app", APP_ID).exists()
+    return _flatpak_ref() is not None
 
 
 def _client_argv() -> list[str] | None:
@@ -323,15 +372,21 @@ def _client_argv() -> list[str] | None:
     behaving exactly as it did. A native binary is the fallback — and on a machine with no
     flatpak client, the thing that makes the plugin work at all. `PF_DECKY_CLIENT=native|flatpak`
     forces one when a machine has both.
+
+    The branch is PINNED (`--branch=`, which keeps the app id last — :func:`_cli_argv` appends
+    `--command=` and flatpak treats everything after the id as the app's own argv), so the client
+    this launches is the exact ref :func:`_client_update_state` checks and :meth:`Plugin.
+    update_client` updates.
     """
     forced = os.environ.get("PF_DECKY_CLIENT", "").strip().lower()
     native = _native_client()
     if forced == "native":
         return [native] if native else None
-    if forced != "flatpak" and not _flatpak_installed() and native:
+    ref = _flatpak_ref()
+    if forced != "flatpak" and not ref and native:
         return [native]
-    if _flatpak_installed():
-        return [_flatpak(), "run", "--arch=x86_64", APP_ID]
+    if ref:
+        return [_flatpak(), "run", f"--arch={_FLATPAK_ARCH}", f"--branch={ref['branch']}", APP_ID]
     return [native] if native else None
 
 
@@ -575,27 +630,44 @@ def _looks_outdated(stderr: str) -> bool:
 
 
 async def _client_update_state() -> dict:
-    """Is a newer commit of the flatpak client available in the remote it tracks? The client is a
-    **per-user** install (so ``sudo flatpak update``, which is system-scope, never touches it), and
-    it versions independently of this plugin — so we compare the installed commit against the
-    remote's here and let the QAM offer a user-scope update. Best-effort; all-``False`` on any error
-    (not installed, no flatpak, offline).
+    """Is a newer commit of the flatpak client available in the remote it tracks? The client
+    versions independently of this plugin, so we compare the installed commit against the
+    remote's here and let the QAM offer an update in the scope the client is actually installed
+    in — a per-user install is one ``sudo flatpak update`` (system-scope) never reaches.
 
     Flatpak keeps its OWN comparison (commits, not versions) because it is the exact one: a
     flatpak built from main between releases carries the release's crate version, so the
     signed-manifest comparison the native path uses would call it up to date when it isn't.
-    Native installs have no commit to compare and go through :func:`_native_update_state`."""
-    state = {"available": False, "installed": "", "remote": ""}
-    rc, info = await _flatpak_capture(["info", "--user", APP_ID], timeout=10.0)
+    Native installs have no commit to compare and go through :func:`_native_update_state`.
+
+    ⚠ Every query names the ref IN FULL (see :func:`_flatpak_ref`) — the remote publishes both
+    `stable` and `canary`, and an unqualified one is an error, not a default."""
+    state = {"available": False, "installed": "", "remote": "", "error": ""}
+    ref = _flatpak_ref()
+    if not ref:
+        return state  # no flatpak client in either scope
+    scope, full = ref["scope"], ref["ref"]
+    rc, info = await _flatpak_capture(["info", scope, full], timeout=10.0)
     if rc != 0:
-        return state  # client not installed as a user app / no flatpak
+        decky.logger.warning("flatpak info %s %s failed (rc=%s): %s", scope, full, rc, info[-200:])
+        state["error"] = "client-unavailable"
+        return state
     state["installed"] = _field_from(info, "Commit")
     origin = _field_from(info, "Origin")
     if not origin:
+        state["error"] = "no-origin"  # a sideloaded bundle tracks no remote to compare against
         return state
-    rc, rinfo = await _flatpak_capture(["remote-info", "--user", origin, APP_ID], timeout=25.0)
+    rc, rinfo = await _flatpak_capture(["remote-info", scope, origin, full], timeout=25.0)
     if rc != 0:
-        return state  # remote unreachable — treat as "up to date", retry next check
+        # ⭐ NOT "up to date". Silently swallowing this is precisely how the whole leg stayed
+        # broken in the field: an unqualified ref made every one of these calls fail, and
+        # returning `available=False` dressed the failure up as good news. A check that could
+        # not run says so, and the panel says so too.
+        decky.logger.warning(
+            "flatpak remote-info %s %s failed (rc=%s): %s", origin, full, rc, rinfo.strip()[-200:]
+        )
+        state["error"] = "fetch-failed"
+        return state
     state["remote"] = _field_from(rinfo, "Commit")
     state["available"] = bool(
         state["installed"] and state["remote"] and state["installed"] != state["remote"]
@@ -946,8 +1018,9 @@ class Plugin:
     async def update_client(self) -> dict:
         """Update the **client**, by whichever route this box's install actually supports.
 
-        * **flatpak** — ``flatpak update --user`` in the USER installation, the scope a Steam
-          Deck install lives in and which ``sudo flatpak update`` (system-scope) never reaches.
+        * **flatpak** — ``flatpak update`` against the FULL ref, in the scope the client is
+          installed in (a per-user install is one ``sudo flatpak update`` never reaches, and an
+          unqualified ref is an error on a remote publishing more than one branch).
         * **native, one-tap capable** (.deb / .rpm / pacman with the packaged root helper and
           the operator's group opt-in) — ``punktfunk-client --apply-update``, which starts the
           fixed, parameterless ``punktfunk-client-update.service`` through polkit. This backend
@@ -960,18 +1033,22 @@ class Plugin:
         """
         if not _client_is_flatpak():
             return await self._update_native_client()
-        _, before = await _flatpak_capture(["info", "--user", APP_ID], timeout=10.0)
+        ref = _flatpak_ref()
+        if not ref:
+            return {"ok": False, "updated": False, "error": "client-unavailable"}
+        scope, full = ref["scope"], ref["ref"]
+        _, before = await _flatpak_capture(["info", scope, full], timeout=10.0)
         before_commit = _field_from(before, "Commit")
-        rc, out = await _flatpak_capture(["update", "--user", "-y", APP_ID], timeout=300.0)
+        rc, out = await _flatpak_capture(["update", scope, "-y", full], timeout=300.0)
         if rc != 0:
             decky.logger.warning("flatpak client update failed (rc=%s): %s", rc, out[-400:])
             return {"ok": False, "updated": False, "error": "update-failed"}
-        _, after = await _flatpak_capture(["info", "--user", APP_ID], timeout=10.0)
+        _, after = await _flatpak_capture(["info", scope, full], timeout=10.0)
         after_commit = _field_from(after, "Commit")
         updated = bool(before_commit and after_commit and before_commit != after_commit)
         decky.logger.info(
-            "flatpak client update: %s -> %s (updated=%s)",
-            before_commit[:10], after_commit[:10], updated,
+            "flatpak client update (%s %s): %s -> %s (updated=%s)",
+            scope, full, before_commit[:10], after_commit[:10], updated,
         )
         _update_cache["data"] = None  # invalidate the cached "update available" snapshot
         return {"ok": True, "updated": updated}
@@ -1018,12 +1095,20 @@ class Plugin:
         try:
             if _client_is_flatpak():
                 cu = await _client_update_state()
+                ref = _flatpak_ref()
                 result["client_update_available"] = bool(cu["available"])
                 result["client_current"] = (cu["installed"] or "")[:10]
                 result["client_latest"] = (cu["remote"] or "")[:10]
                 result["client_install"] = "flatpak"
                 result["client_applier"] = "flatpak"
-                result["client_command"] = f"flatpak update --user {APP_ID}"
+                # The line a user could actually run — same scope, same full ref we use. The old
+                # unqualified one errored out ("Multiple branches available") when pasted, too.
+                result["client_command"] = (
+                    f"flatpak update {ref['scope']} -y {ref['ref']}" if ref else ""
+                )
+                if cu["error"]:
+                    # Same contract as the native leg: "couldn't tell" is never "up to date".
+                    result["client_error"] = cu["error"]
             else:
                 nu = await _native_update_state()
                 result["client_update_available"] = bool(nu.get("update_available"))

clients/decky/scripts/test-backend.py

@@ -30,6 +30,10 @@ sys.modules["decky"] = decky
 sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
 import main  # noqa: E402  (the plugin backend)
 
+# The argv fixtures below monkey-patch `_client_argv` to pin one install shape; the
+# _flatpak_ref block wants the REAL resolver back, so keep a handle on it.
+_real_client_argv = main._client_argv
+
 failures = 0
 
 
@@ -75,6 +79,60 @@ check("cli argv: native without a sibling CLI is None", main._cli_argv() is None
 (tmp / "punktfunk").write_text("")
 check("cli argv: native sibling found", main._cli_argv() == [str(tmp / "punktfunk")])
 
+# ---- _flatpak_ref: the branch must be NAMED, always ---------------------------------------
+#
+# The bug this exists to prevent: every client-update query used to name no branch, and the
+# punktfunk remote publishes `stable` AND `canary` — so `flatpak remote-info <origin>
+# io.unom.Punktfunk` failed with "Multiple branches available", the check swallowed the failure,
+# and the panel reported the client up to date forever. One branch INSTALLED is not enough to
+# make the query unambiguous; the ambiguity lives on the remote.
+shutil.rmtree("/tmp/pf-test-home", ignore_errors=True)
+_fp_root = Path("/tmp/pf-test-home/.local/share/flatpak/app/io.unom.Punktfunk/x86_64")
+main._flatpak = lambda: "/usr/bin/flatpak"
+main._client_argv = _real_client_argv  # undo the fixture patches above
+
+check("ref: nothing installed => None", main._flatpak_ref() is None)
+
+
+def _install_branch(name: str):
+    """A deployed branch: the `active` symlink is what distinguishes an install from leftovers."""
+    commit = _fp_root / name / "deadbeef"
+    commit.mkdir(parents=True, exist_ok=True)
+    (_fp_root / name / "active").symlink_to("deadbeef")
+
+
+(_fp_root / "canary").mkdir(parents=True, exist_ok=True)
+check("ref: a branch dir without `active` is leftovers, not an install", main._flatpak_ref() is None)
+
+_install_branch("canary")
+ref = main._flatpak_ref()
+check("ref: the single installed branch is used", ref == {
+    "scope": "--user", "branch": "canary", "ref": "io.unom.Punktfunk//canary",
+})
+check(
+    "ref: the launcher pins that branch, app id still LAST",
+    main._client_argv() == [
+        "/usr/bin/flatpak", "run", "--arch=x86_64", "--branch=canary", "io.unom.Punktfunk",
+    ],
+)
+# The pin must survive _cli_argv's rewrite, or the CLI runs a different build than the GUI.
+check(
+    "ref: --command= is inserted before the app id, keeping the pin",
+    main._cli_argv() == [
+        "/usr/bin/flatpak", "run", "--arch=x86_64", "--branch=canary",
+        "--command=punktfunk", "io.unom.Punktfunk",
+    ],
+)
+
+# Two installed: `stable` is what a plain `flatpak run` resolves to, so it must be what we
+# check and update too — otherwise a leftover stale `stable` wins the launch while `canary`
+# gets the update, and the two halves disagree about which client is even running.
+_install_branch("stable")
+check("ref: with both installed, stable wins (what `flatpak run` picks)",
+      main._flatpak_ref()["branch"] == "stable")
+
+shutil.rmtree("/tmp/pf-test-home", ignore_errors=True)
+
 # ---- _cli_error: the CLI's exit-code contract -------------------------------------------
 #
 # Exit 5 + `unknown command` is how a client too old for a verb announces itself — the ONE

clients/decky/src/backend.ts

@@ -120,7 +120,9 @@ export interface UpdateInfo {
   client_applier: string;
   client_command: string; // one copy-pastable line that updates this install by hand
   client_opt_in: string; // set when one-tap WOULD work after `usermod -aG punktfunk-update`
-  client_error?: string; // the client check couldn't complete (e.g. "client-outdated")
+  // The client check couldn't complete — NEVER rendered as "up to date". "client-outdated" |
+  // "client-unavailable" | "no-origin" | "fetch-failed" (flatpak: the remote was unreachable).
+  client_error?: string;
   error?: string; // "update-channel-unknown" (dev build) | "fetch-failed"
 }
 

clients/decky/src/index.tsx

@@ -33,6 +33,7 @@ import {
   applyUpdate,
   checkForUpdatesNow,
   clientUpdateIsManualOnly,
+  clientUpdateIsOneTap,
   hasUpdate,
   HostView,
   needsPair,
@@ -183,8 +184,11 @@ const QamPanel: FC = () => {
                 onClick={() => applyUpdate(update!, check)}
                 label={
                   update!.update_available
-                    ? `Plugin v${update!.current} → v${update!.latest}${
-                        update!.client_update_available ? " + client" : ""
+                    ? // "+ client" only when this tap will really install it. A manual-only
+                      // client rides along as a toast with the command, and promising it in the
+                      // label would make that read as a failure.
+                      `Plugin v${update!.current} → v${update!.latest}${
+                        clientUpdateIsOneTap(update) ? " + client" : ""
                       }`
                     : "New client version"
                 }

clients/session/src/main.rs

@@ -325,6 +325,22 @@ mod session_main {
         };
         // Before the struct literal — `vulkan` moves into it below.
         let phase_lock = vulkan.as_ref().is_some_and(|v| v.present_timing);
+        // …and the 4:4:4 promise, for the same reason: asked while the device bundle is
+        // still borrowable. `&&` short-circuits, so a box that never enabled Full chroma
+        // pays no capability queries for a feature it does not want.
+        let want_444 = settings.enable_444
+            && pf_client_core::video::hevc_444_hardware_decodable(vulkan.as_ref());
+        if settings.enable_444 && !want_444 {
+            // Loud, because the user turned a switch on and is not getting it. The
+            // alternative is what this replaces: the host grants 4:4:4, the decode ladder
+            // has no rung that can take it, and the session drops HEVC entirely.
+            tracing::warn!(
+                "Full chroma (4:4:4) requested but this device has no 4:4:4 HEVC decode — \
+                 asking for 4:2:0 instead. Advertising it would cost the whole codec: 4:4:4 \
+                 is granted on HEVC only, and there is no software HEVC decoder to fall back \
+                 to (PyroWave carries 4:4:4 on any GPU, if the link can take it)."
+            );
+        }
         SessionParams {
             host: addr,
             port,
@@ -356,30 +372,16 @@ mod session_main {
             // slice NALs, so the host may keep its multi-slice low-latency default (§7 LN1).
             // The mobile/TV embedders must NOT copy this blindly — Amlogic MediaCodec wedges
             // on multi-slice AUs (see `VIDEO_CAP_MULTI_SLICE`), so they advertise per-decoder.
-            // 4:4:4 is opt-in and off by default (Settings "Full chroma"): the bit only says
+            // 4:4:4 is opt-in and off by default (Settings "Full chroma"): the bit says
             // "upgrade me if you can" — the host still gates on its own policy, its capturer,
             // HEVC, and a real GPU 4:4:4 encode probe, and answers the resolved chroma in the
-            // Welcome BEFORE we build a decoder. Advertised whenever the user asks because
-            // every path can DISPLAY it: the Vulkan presenter samples the 2-plane 4:4:4 pool
-            // formats (hardware RExt decode where the driver offers it — NVIDIA today),
-            // with the decoder ladder demoting on its own. No capability probe gates the
-            // bit — but note (M8) that the software rung below it is 4:2:0 8-bit ONLY and
-            // refuses anything else rather than mis-scaling it, so on a box whose hardware
-            // 4:4:4 decode fails the floor is a codec fallback, not a converted picture.
+            // Welcome BEFORE we build a decoder. It is now ALSO gated on this device being
+            // able to decode 4:4:4 (`want_444`, computed above); the rule and its reasoning
+            // live in `video::video_caps_for`, which is where they get tested.
             // The cost stays VISIBLE, not silent: the Detailed stats overlay prints the
             // resolved chroma ("4:4:4→4:2:0" when the host declined) and the decode path
             // frames actually took.
-            video_caps: punktfunk_core::quic::VIDEO_CAP_MULTI_SLICE
-                | if settings.hdr_enabled {
-                    punktfunk_core::quic::VIDEO_CAP_10BIT | punktfunk_core::quic::VIDEO_CAP_HDR
-                } else {
-                    0
-                }
-                | if settings.enable_444 {
-                    punktfunk_core::quic::VIDEO_CAP_444
-                } else {
-                    0
-                },
+            video_caps: pf_client_core::video::video_caps_for(settings.hdr_enabled, want_444),
             // This panel's HDR colour volume → the host's virtual-display EDID, so host
             // apps tone-map to the real glass. Windows reads it from DXGI (the
             // `--window-pos` monitor; advanced-color outputs only) — gated on the HDR
@@ -496,6 +498,12 @@ mod session_main {
     /// decode is already the default just no-ops. Append rather than clobber so a user's own
     /// `RADV_PERFTEST` survives; `PUNKTFUNK_DECODER=native-vaapi` still overrides the decoder
     /// choice (the pre-M10 `vaapi` spelling reaches the same rung — it migrates, loudly).
+    ///
+    /// ⚠⚠ Called from the TOP of [`run`], ahead of the `--list-adapters` / `--probe-decode`
+    /// early exits — not merely "before `run_session` creates the instance". Those flags
+    /// create Vulkan instances of their own and RADV latches `RADV_PERFTEST` when its ICD
+    /// initialises, so a call placed after them leaves the triage tool describing a device
+    /// that cannot decode while the streaming path decodes on it.
     #[cfg(target_os = "linux")]
     fn enable_radv_video_decode() {
         const TOKEN: &str = "video_decode";
@@ -579,6 +587,23 @@ mod session_main {
             )
             .init();
 
+        // Before ANY Vulkan call — and that includes the two probe flags below, which is the
+        // whole reason this sits at the top of `run` instead of beside the session setup it
+        // was written for. Make RADV expose its video-decode queue + extensions so the
+        // decoder's `auto` path prefers Vulkan Video over VAAPI (Steam Deck, and any gated
+        // RADV). Windows drivers (NVIDIA/AMD Adrenalin) expose theirs unconditionally.
+        //
+        // ⚠⚠ It USED to sit after the `--list-adapters` / `--probe-decode` / `--list-audio` /
+        // `--pair` early exits, which meant the triage tool answered a DIFFERENT question from
+        // the one the streaming path asks. Measured on a Steam Deck (2026-08-08, canary
+        // `e22af40f`), same binary, back to back: bare `--probe-decode` printed `vulkan video
+        // decode: no`, `driver decode ops: none (0x0)`, `no queue family advertises
+        // VIDEO_DECODE`; the same call with `RADV_PERFTEST=video_decode` in the environment
+        // printed `YES` and `H.264, H.265, AV1, VP9`. The tool exists to be believed, so any
+        // Deck triage that consulted it reached the opposite of the truth.
+        #[cfg(target_os = "linux")]
+        enable_radv_video_decode();
+
         // `--list-adapters`: print the Vulkan physical devices' marketing names (one per
         // line, discrete first) for the desktop shells' GPU picker, then exit.
         if arg_flag("--list-adapters") {
@@ -753,11 +778,8 @@ mod session_main {
             return headless_pair(&pin);
         }
 
-        // Before any Vulkan call: make RADV expose its video-decode queue + extensions so the
-        // decoder's `auto` path prefers Vulkan Video over VAAPI (Steam Deck, and any gated RADV).
-        // Windows drivers (NVIDIA/AMD Adrenalin) expose theirs unconditionally.
-        #[cfg(target_os = "linux")]
-        enable_radv_video_decode();
+        // (The RADV video-decode opt-in that used to live here now runs at the very top of
+        // `run` — it has to precede the probe flags too, not just the session.)
 
         // The Settings device picks → env, unless the user already forced one by hand:
         // the GPU (the shells' pickers store the adapter's marketing name) for the

crates/pf-capture/src/linux/mod.rs

@@ -168,6 +168,10 @@ pub struct PortalCapturer {
     /// downgrade ([`pf_zerocopy::note_raw_dmabuf_negotiation_failed`]) so the pipeline rebuild
     /// retries on the CPU offer instead of failing identically forever.
     vaapi_dmabuf: bool,
+    /// PW3: this capture's dmabuf offer has been confirmed to negotiate (a frame arrived), so the
+    /// negotiation retry budget has already been credited back. One-shot — the credit is per
+    /// capture, not per frame.
+    negotiation_confirmed: bool,
     /// This capture ran the HDR (10-bit PQ/BT.2020 dmabuf) offer — see [`Self::open`]'s
     /// `want_hdr`. Read by the negotiation-timeout diagnosis (a failed HDR offer latches the
     /// process-wide SDR downgrade) and by [`hdr_meta`](Capturer::hdr_meta).
@@ -412,6 +416,7 @@ impl PwHandles {
             signals: self.signals,
             stall_since: None,
             vaapi_dmabuf: self.vaapi_dmabuf,
+            negotiation_confirmed: false,
             hdr_offer: self.hdr_offer,
             hdr_source,
             node_id,
@@ -468,6 +473,13 @@ fn spawn_pipewire(
     } else {
         want_hdr
     };
+    // PW3: tell the raw-dmabuf latch which capture this is BEFORE reading its verdict below. A
+    // different node id is a different question — a fresh virtual output, a compositor restart,
+    // the Bazzite Gaming↔Desktop switch — and inheriting "dmabuf does not work here" from an
+    // unrelated capture is how one transient timeout used to cost a host CPU capture until it was
+    // restarted. The portal bit is in the key because a portal-fd capture and a virtual-output
+    // capture with the same node number are genuinely different sources.
+    pf_zerocopy::note_raw_dmabuf_capture(u64::from(node_id) | (u64::from(fd.is_some()) << 32));
     // THE negotiation decision, resolved once here and handed to the thread — no mirror (L3/F1).
     // Every environment/latch read the decision depends on happens at this single point.
     let plan = pipewire::negotiation_plan(pipewire::NegotiationInputs {
@@ -705,6 +717,7 @@ impl PortalCapturer {
             // The slot before the wakeup: a publish that coalesced its edge (or landed while we were
             // not waiting) is still visible here.
             if let Some(f) = self.take_frame() {
+                self.note_negotiation_confirmed();
                 return Ok(f);
             }
             let slice = Duration::from_millis(500)
@@ -728,6 +741,16 @@ impl PortalCapturer {
         self.slot.lock().ok().and_then(|mut s| s.take())
     }
 
+    /// PW3: a frame arrived, so this capture's dmabuf-only offer DID negotiate — credit the
+    /// negotiation retry budget back. Only meaningful for a capture that actually made that offer,
+    /// and only once per capture (the budget counts consecutive failed BUILDS, not frames).
+    fn note_negotiation_confirmed(&mut self) {
+        if self.vaapi_dmabuf && !self.negotiation_confirmed {
+            self.negotiation_confirmed = true;
+            pf_zerocopy::note_raw_dmabuf_negotiation_ok();
+        }
+    }
+
     /// The [`frame_within`](Self::frame_within) budget expired (or the thread ended) — turn it
     /// into the diagnosis-bearing error. Split out of the slicing loop above; behavior unchanged.
     fn next_frame_timed_out(

crates/pf-capture/src/linux/pw_pods.rs

@@ -288,16 +288,57 @@ pub(super) fn build_shm_only_buffers() -> Result<Vec<u8>> {
     })
 }
 
-/// Build a Buffers param requesting dmabuf-only buffers.
+/// PW5 stage 2: the buffer-pool depth we ASK for on the zero-copy path, as a Choice range.
+///
+/// The zero-copy path hands the SPA buffer back to the producer at `.process` return, while the
+/// encode thread still holds a dup of its dmabuf fd and has not yet imported, let alone read, the
+/// contents. Nothing bounds that window — see the `queue_raw_buffer` comment in `pipewire.rs` — so
+/// the only thing that keeps capture untorn is the producer round-robining a pool deeper than our
+/// import+encode latency. Until PW5 stage 1 nobody had ever counted what that pool was; we never
+/// even asked for a size (`build_dmabuf_buffers` set `dataType` and nothing else).
+///
+/// A **range**, deliberately, not a fixed count: SPA intersects the consumer's and producer's
+/// Buffers params, so a fixed 8 against a producer that can only afford 4 empties the intersection
+/// and the link silently stalls in "negotiating" — the exact failure mode the cursor-meta `size`
+/// property already cost this codebase once (see `build_cursor_meta_param`). With a range the
+/// producer clamps into it and negotiation still succeeds.
+///
+/// The numbers: `min` stays at 2 so nothing that works today stops working; `default` 8 is ~133 ms
+/// of buffer at 60 Hz and ~33 ms at 240 Hz, comfortably past the ~3-4 ms capture→fence latency
+/// measured in PW3/PW4 even with a second frame in flight; `max` 16 is a ceiling, not a request
+/// (a 4K 4:4:4 buffer is ~25 MB, so 16 is ~400 MB of compositor allocation and worth capping).
+/// **What the producer actually picks is logged by the stage-1 census — trust that line, not
+/// these constants.**
+const POOL_MIN: i32 = 2;
+const POOL_DEFAULT: i32 = 8;
+const POOL_MAX: i32 = 16;
+
+/// Build a Buffers param requesting dmabuf-only buffers, with pool headroom (see [`POOL_DEFAULT`]).
 pub(super) fn build_dmabuf_buffers() -> Result<Vec<u8>> {
     serialize_pod(pw::spa::pod::Object {
         type_: pw::spa::utils::SpaTypes::ObjectParamBuffers.as_raw(),
         id: pw::spa::param::ParamType::Buffers.as_raw(),
-        properties: vec![pw::spa::pod::Property {
-            key: pw::spa::sys::SPA_PARAM_BUFFERS_dataType,
-            flags: pw::spa::pod::PropertyFlags::empty(),
-            value: pw::spa::pod::Value::Int(1i32 << pw::spa::sys::SPA_DATA_DmaBuf),
-        }],
+        properties: vec![
+            pw::spa::pod::Property {
+                key: pw::spa::sys::SPA_PARAM_BUFFERS_dataType,
+                flags: pw::spa::pod::PropertyFlags::empty(),
+                value: pw::spa::pod::Value::Int(1i32 << pw::spa::sys::SPA_DATA_DmaBuf),
+            },
+            pw::spa::pod::Property {
+                key: pw::spa::sys::SPA_PARAM_BUFFERS_buffers,
+                flags: pw::spa::pod::PropertyFlags::empty(),
+                value: pw::spa::pod::Value::Choice(pw::spa::pod::ChoiceValue::Int(
+                    pw::spa::utils::Choice(
+                        pw::spa::utils::ChoiceFlags::empty(),
+                        pw::spa::utils::ChoiceEnum::Range {
+                            default: POOL_DEFAULT,
+                            min: POOL_MIN,
+                            max: POOL_MAX,
+                        },
+                    ),
+                )),
+            },
+        ],
     })
 }
 
@@ -512,4 +553,47 @@ mod tests {
             "libspa renumbered spa_video_transfer_function — update the hardcoded PQ id"
         );
     }
+
+    /// PW5 stage 2: the pool request must be a **Choice Range**, never a fixed Int.
+    ///
+    /// This is the whole safety argument for asking at all: SPA intersects the two sides' Buffers
+    /// params, so a fixed count a producer cannot afford empties the intersection and the link
+    /// stalls in "negotiating" with no error anywhere — the same trap that cost this codebase the
+    /// entire Linux cursor channel once (see `build_cursor_meta_param`). Asserting the pod shape
+    /// is what keeps a later "simplify" from turning the range back into a number.
+    #[test]
+    fn the_dmabuf_pool_request_is_a_range_not_a_fixed_count() {
+        let pod = build_dmabuf_buffers().unwrap();
+        let key = spa::sys::SPA_PARAM_BUFFERS_buffers.to_ne_bytes();
+        let at = pod
+            .windows(4)
+            .position(|w| w == key)
+            .expect("the dmabuf Buffers pod must carry a buffers count");
+        let word = |off: usize| u32::from_ne_bytes(pod[off..off + 4].try_into().unwrap());
+        // Property = { key, flags, value_pod }; value_pod = { size, type, body }. A Choice body
+        // is { type: u32, flags: u32, child_size: u32, child_type: u32, values… }.
+        assert_eq!(
+            word(at + 12),
+            spa::sys::SPA_TYPE_Choice,
+            "the buffers count must be a Choice, not a bare Int — a fixed count can fail \
+             negotiation outright"
+        );
+        assert_eq!(
+            word(at + 16),
+            spa::sys::SPA_CHOICE_Range,
+            "the Choice must be a Range (default, min, max)"
+        );
+        assert_eq!(word(at + 24), 4, "Choice child pods are 4-byte Ints");
+        assert_eq!(word(at + 28), spa::sys::SPA_TYPE_Int, "…of type Int");
+        let vals: Vec<i32> = (0..3)
+            .map(|i| i32::from_ne_bytes(pod[at + 32 + i * 4..at + 36 + i * 4].try_into().unwrap()))
+            .collect();
+        assert_eq!(
+            vals,
+            vec![POOL_DEFAULT, POOL_MIN, POOL_MAX],
+            "Range values are serialized default-first"
+        );
+        // The minimum must not exceed what producers already serve, or the ask becomes a demand.
+        const { assert!(POOL_MIN <= 2) };
+    }
 }

crates/pf-capture/src/windows/idd_push.rs

@@ -547,7 +547,8 @@ pub struct IddPushCapturer {
     _keepalive: Box<dyn Send>,
 }
 // SAFETY: `IddPushCapturer` is `!Send` only because of its `*mut SharedHeader` raw pointer (and the
-// COM interfaces / the broker's bare control `HANDLE`, which is process-global and never closed). It is
+// COM interfaces; the frame/cursor delivery closures own `Arc` clones of the control device and are
+// `Send + Sync` on their own). It is
 // created, used, and dropped by a SINGLE thread — the owning capture/encode thread — never shared: the
 // `ID3D11DeviceContext` is the device's IMMEDIATE context (single-threaded by D3D11 contract) and is
 // only ever touched from that thread, and the header pointer (into the mapping this struct owns) is

crates/pf-client-core/Cargo.toml

@@ -134,6 +134,12 @@ pf-vaadec = { path = "../pf-vaadec" }
 # container can then compile and clippy the whole rung without `libva-dev`, and a machine
 # without a VAAPI runtime gets a clean refusal instead of a packaging dependency.
 libloading = "0.8"
+# The gamescope overlay watcher (`overlay_focus`): read two CARDINAL properties off a
+# gamescope root window and block on PropertyNotify. `default-features = false` keeps the
+# pure-Rust `RustConnection` — no libxcb link, so no new C dependency on any client package
+# — the same stance pf-capture and pf-vdisplay already take on this crate. No extension
+# features: root-window properties and an event mask are core X11.
+x11rb = { version = "0.13", default-features = false }
 
 [target.'cfg(windows)'.dependencies]
 wasapi = "0.23"

crates/pf-client-core/src/gamepad.rs

@@ -381,6 +381,7 @@ enum Ctl {
     PadAudioPrefs(u8),
     MenuMode(bool),
     MenuRumble(MenuPulse),
+    Mask(bool),
 }
 
 #[derive(Clone)]
@@ -548,6 +549,31 @@ impl GamepadService {
         let _ = self.ctl.send(Ctl::Forwarding(on));
     }
 
+    /// A system overlay owns the controller right now — hold every forwarded pad NEUTRAL
+    /// until it closes. This is the Steam Input behaviour a streaming client has to
+    /// reproduce by hand: while the Deck's Steam menu or QAM is up, the same physical
+    /// sticks and buttons drive Steam's UI, and anything we keep forwarding lands in the
+    /// game underneath as a second, invisible player.
+    ///
+    /// **Masking is not [`set_forwarding`](Self::set_forwarding).** Forwarding-off closes the
+    /// slot and sends the host a [`GamepadRemove`](InputKind::GamepadRemove) — the game sees a
+    /// controller *unplug*, which is a hardware event with real in-game consequences (pause
+    /// menus, "reconnect your controller", player-slot churn). Opening the QAM must not look
+    /// like that. Masking keeps every slot open and merely stops the transitions, after
+    /// flushing what the host believes is held so a stick held at overlay-open stops steering
+    /// instead of freezing at its last value.
+    ///
+    /// SDL has this gate of its own — it drops presses while the process has windows but no
+    /// keyboard focus — and on a desktop it fires. It CANNOT fire on a Deck in Gaming Mode:
+    /// gamescope resolves focus per Xwayland ctx, and the client sits alone in its own ctx, so
+    /// its X input focus never moves when the overlay takes over (measured). That is why this
+    /// exists as an explicit lever rather than something inherited for free.
+    ///
+    /// Held state is adopted, not replayed, on the way back — see [`Ctl::Mask`]'s handling.
+    pub fn set_masked(&self, on: bool) {
+        let _ = self.ctl.send(Ctl::Mask(on));
+    }
+
     /// The session's system-button policy, resolved from
     /// [`Settings::system_buttons_forward`] × [`Settings::guide_gesture_enabled`]:
     /// `forward_raw` gates the physical guide/QAM presses onto the wire (off = they stay
@@ -1069,6 +1095,9 @@ struct Worker {
     menu_mode: bool,
     menu_nav: MenuNav,
     menu_tx: async_channel::Sender<MenuEvent>,
+    /// A system overlay owns input ([`GamepadService::set_masked`]): forwarded pads are held
+    /// neutral and menu translation is paused, with every slot still OPEN.
+    masked: bool,
 }
 
 impl Worker {
@@ -1519,6 +1548,87 @@ impl Worker {
         }
     }
 
+    /// Re-adopt what the pads are physically holding when an overlay mask lifts.
+    ///
+    /// Buttons are taken back into `held_buttons` **without** a wire press: a button pressed
+    /// inside the overlay (the A that picked a QAM row) must not fire in the game the instant it
+    /// closes — releasing it and pressing again is what arms it. Same rule menu mode already
+    /// applies across a screen handoff ([`MenuNav::reset`]), for the same reason.
+    ///
+    /// Axes ARE re-sent, because a stick has no press semantics to ghost — it is deflected or it
+    /// is not. The mask flushed them to zero, and SDL only speaks on *change*, so a stick still
+    /// held when the overlay closes would stay dead host-side until the user happened to move it.
+    ///
+    /// Neither half can run against a pad that is gone: this only walks open slots, and every SDL
+    /// read here is a state query on a handle the slot owns.
+    fn readopt_held(&mut self) {
+        use sdl3::gamepad::{Axis, Button};
+        // Every button `button_bit` maps — the same surface the press path forwards.
+        const BUTTONS: [Button; 21] = [
+            Button::South,
+            Button::East,
+            Button::West,
+            Button::North,
+            Button::Back,
+            Button::Start,
+            Button::Guide,
+            Button::LeftStick,
+            Button::RightStick,
+            Button::LeftShoulder,
+            Button::RightShoulder,
+            Button::DPadUp,
+            Button::DPadDown,
+            Button::DPadLeft,
+            Button::DPadRight,
+            Button::Touchpad,
+            Button::RightPaddle1,
+            Button::LeftPaddle1,
+            Button::RightPaddle2,
+            Button::LeftPaddle2,
+            Button::Misc1,
+        ];
+        const AXES: [Axis; 6] = [
+            Axis::LeftX,
+            Axis::LeftY,
+            Axis::RightX,
+            Axis::RightY,
+            Axis::TriggerLeft,
+            Axis::TriggerRight,
+        ];
+        // Copied out: the slot walk below borrows `self` mutably.
+        let system_forward = self.system_forward;
+        let attached = self.attached.clone();
+        for slot in &mut self.slots {
+            slot.held_buttons.clear();
+            for b in BUTTONS {
+                let Some(bit) = button_bit(b) else {
+                    continue;
+                };
+                // The press path returns before `held_buttons` for un-forwarded system
+                // buttons; tracking them here would invent state it never keeps.
+                if !system_forward && matches!(bit, wire::BTN_GUIDE | wire::BTN_MISC1) {
+                    continue;
+                }
+                if slot.pad.button(b) {
+                    slot.held_buttons.push(bit);
+                }
+            }
+            let Some(c) = &attached else {
+                continue;
+            };
+            for a in AXES {
+                let (id, v) = axis_value(a, slot.pad.axis(a));
+                if slot.last_axis[id as usize] != v {
+                    slot.last_axis[id as usize] = v;
+                    send(c, InputKind::GamepadAxis, id, v, slot.index);
+                }
+            }
+        }
+        // The chord latch was cleared on the way in; drop it again if what we just adopted
+        // doesn't actually hold it.
+        self.rearm_escape();
+    }
+
     /// True when any one forwarded pad holds the entire escape chord (any player can leave).
     fn chord_held(&self) -> bool {
         self.slots
@@ -1785,6 +1895,34 @@ impl Worker {
                             .push((pad, bit, Instant::now() + TAP_PRESS));
                     }
                 }
+                Ok(Ctl::Mask(on)) => {
+                    if self.masked == on {
+                        continue;
+                    }
+                    self.masked = on;
+                    if on {
+                        // Neutral NOW, and while the slots stay open: a stick held when the
+                        // overlay opened must stop steering, but the host must not see the pad
+                        // unplug (that is `close_slot_at`'s job, and a game reacts to it).
+                        if let Some(c) = self.attached.clone() {
+                            for slot in &mut self.slots {
+                                Self::flush_slot(&c, slot);
+                            }
+                        }
+                        // Nothing can be mid-chord across the flip: the transitions that would
+                        // complete or break it are about to be dropped.
+                        self.reset_chord();
+                    } else {
+                        // Coming back. Whatever is still physically held was never delivered —
+                        // adopt it silently rather than replay it as a fresh press, the same
+                        // rule menu mode uses across a screen handoff (`MenuNav::reset`). A
+                        // button you pressed *inside* the overlay must not fire in the game the
+                        // instant it closes; releasing and pressing again is what arms it.
+                        self.readopt_held();
+                        self.menu_nav.reset();
+                    }
+                    tracing::info!(masked = on, "overlay input mask");
+                }
                 Ok(Ctl::Forwarding(on)) => {
                     if self.forwarding == on {
                         continue;
@@ -1846,6 +1984,28 @@ impl Worker {
     /// "is a session live".
     fn handle_event(&mut self, event: sdl3::event::Event) {
         use sdl3::event::Event;
+        // A system overlay owns the controller ([`GamepadService::set_masked`]): drop every
+        // input transition. The pads were flushed neutral when the mask went on, so dropping
+        // the ups as well as the downs is what keeps the two in agreement — `readopt_held`
+        // rebuilds the held set from the hardware when it lifts.
+        //
+        // Device add/remove deliberately still count: a controller genuinely plugged in or
+        // pulled out behind an overlay is a fact about the world, not an input, and losing it
+        // would leave the slot table lying about what exists.
+        if self.masked
+            && matches!(
+                event,
+                Event::ControllerButtonDown { .. }
+                    | Event::ControllerButtonUp { .. }
+                    | Event::ControllerAxisMotion { .. }
+                    | Event::ControllerTouchpadDown { .. }
+                    | Event::ControllerTouchpadMotion { .. }
+                    | Event::ControllerTouchpadUp { .. }
+                    | Event::ControllerSensorUpdated { .. }
+            )
+        {
+            return;
+        }
         match event {
             Event::ControllerDeviceAdded { which, .. } => {
                 if !self.order.contains(&which) {
@@ -2074,7 +2234,9 @@ impl Worker {
     /// on and no session is attached (attach supersedes; SDL events merely wake the loop,
     /// so a press is translated the iteration it arrives).
     fn menu_poll(&mut self) {
-        if !self.menu_mode || self.attached.is_some() {
+        // Masked covers the launcher too: with the Deck's Steam menu up over our console, the
+        // same stick that scrolls Steam's UI would otherwise also be scrolling ours behind it.
+        if !self.menu_mode || self.attached.is_some() || self.masked {
             return;
         }
         let Some((_, pad)) = self.menu_open.as_ref() else {
@@ -2301,6 +2463,7 @@ impl Worker {
             menu_mode: false,
             menu_nav: MenuNav::new(),
             menu_tx,
+            masked: false,
         }
     }
 }

crates/pf-client-core/src/lib.rs

@@ -46,6 +46,10 @@ pub mod orchestrate;
 // The host's OS-identity chain (mDNS `os=` TXT): sanitize + icon-walk order. Pure string
 // logic, built everywhere (the Apple/Android ports mirror it rather than link it).
 pub mod os;
+// "A system overlay owns the controller" for gamescope Gaming Mode — the signal behind the
+// gamepad input mask, which SDL's own focus gate structurally cannot provide there.
+#[cfg(target_os = "linux")]
+pub mod overlay_focus;
 // Client settings profiles: the override catalog + the one connect-time resolver
 // (design/client-settings-profiles.md §4). Sits beside `trust`, which owns the host records
 // the bindings live on.

crates/pf-client-core/src/overlay_focus.rs

@@ -0,0 +1,284 @@
+//! "A system overlay owns the controller right now" — the gamescope half of the input mask.
+//!
+//! On a Steam Deck in Gaming Mode the Steam menu and the QAM are drawn by Steam and driven by
+//! the *same physical controller* the client is forwarding. Steam does not mask us the way it
+//! masks a normal game: masking happens on Steam Input's virtual pad, and the client
+//! deliberately forwards the REAL pad instead (28DE:1205 — the virtual one has no gyro,
+//! trackpads or paddles). So while the QAM is up, one thumbstick drives Steam's UI *and* the
+//! game on the host. This watcher is what tells [`crate::gamepad::GamepadService::set_masked`]
+//! to stop that.
+//!
+//! **Why the free mechanism can't do it.** SDL already drops gamepad presses while the process
+//! has windows but no keyboard focus (`SDL_PrivateJoystickShouldIgnoreEvent`, on by default —
+//! we never set `SDL_JOYSTICK_ALLOW_BACKGROUND_EVENTS`), and on a desktop that fires. It cannot
+//! fire here: gamescope resolves focus **per Xwayland ctx** (`determine_and_apply_focus` scans
+//! only that ctx's window list), the Steam overlay lives in the root ctx, and the client sits
+//! alone in its own. Measured on a Deck 2026-08-08: with the QAM open, X input focus inside the
+//! client's ctx never moved off its window, so no `FocusOut` is ever generated. Hence an
+//! explicit signal.
+//!
+//! **The signal.** gamescope publishes two CARDINALs on the ROOT ctx's root window (Steam mode
+//! only, i.e. `gamescope -e` — which is what Gaming Mode runs):
+//!
+//! * `GAMESCOPE_FOCUSED_APP` — appid of the window holding **input** focus
+//! * `GAMESCOPE_FOCUSED_APP_GFX` — appid of the window being **displayed**
+//!
+//! They are equal in normal play and diverge exactly while something else has taken input over
+//! the running app. Measured, both for the Steam menu and for the QAM:
+//!
+//! ```text
+//! app=3856846079 gfx=3856846079   ← streaming, we own input
+//! app=769        gfx=3856846079   ← overlay open (769 = Steam)
+//! ```
+//!
+//! Note `app != gfx` rather than "app is Steam": anything that takes input away from the
+//! displayed app is a thing we should stop forwarding through, and comparing to our own appid
+//! would need us to know it (a non-Steam shortcut's appid is assigned by Steam at creation).
+//!
+//! **Which display.** Not necessarily ours. Gaming Mode runs `gamescope --xwayland-count 2`:
+//! Steam and the atoms live on the first server, the app is given the second, and the client's
+//! own `$DISPLAY` therefore has none of these properties. So discovery walks candidates — our
+//! `$DISPLAY` first (correct for a single-server gamescope), then every socket in
+//! `/tmp/.X11-unix` — and keeps the first whose root actually carries both atoms. gamescope's
+//! Xwayland accepts unauthenticated local connections (verified: `xprop` against it succeeds
+//! with no `.Xauthority` at all), so no cookie plumbing is needed.
+//!
+//! Everything here is best-effort by construction: no gamescope, no X, a sandbox that cannot
+//! see the other socket, or a session that restarts underneath us all end in "no signal", which
+//! degrades to exactly the behaviour that shipped before this module existed.
+
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Arc;
+use std::time::Duration;
+use x11rb::connection::Connection;
+use x11rb::protocol::xproto::{
+    Atom, AtomEnum, ChangeWindowAttributesAux, ConnectionExt, EventMask, Window,
+};
+use x11rb::protocol::Event;
+use x11rb::rust_connection::RustConnection;
+
+/// How long to wait before rebuilding everything after the X connection drops. Gaming Mode
+/// recreates its Xwayland servers across a session restart, so "gone" is not permanent — but it
+/// is also not worth a hot retry loop.
+const RECONNECT_DELAY: Duration = Duration::from_secs(3);
+
+/// Live "an overlay owns input" flag, updated by a background thread.
+///
+/// Cheap to poll (one relaxed atomic load), which is what the presenter's event loop wants — it
+/// checks once per iteration and only talks to the gamepad service on an edge.
+pub struct OverlayFocus {
+    open: Arc<AtomicBool>,
+}
+
+impl OverlayFocus {
+    /// Start watching, or return `None` when this isn't a gamescope Steam session (the common
+    /// case — every desktop client) or the user opted out with `PUNKTFUNK_OVERLAY_MASK=0`.
+    ///
+    /// Returning `None` is not a failure: the caller keeps its window-focus path, which is the
+    /// right signal everywhere the compositor actually moves focus.
+    pub fn start() -> Option<OverlayFocus> {
+        if std::env::var("PUNKTFUNK_OVERLAY_MASK").is_ok_and(|v| v == "0" || v == "false") {
+            tracing::info!("overlay input mask disabled by PUNKTFUNK_OVERLAY_MASK");
+            return None;
+        }
+        if !gamescope_session() {
+            return None;
+        }
+        let open = Arc::new(AtomicBool::new(false));
+        let flag = open.clone();
+        std::thread::Builder::new()
+            .name("punktfunk-overlay-focus".into())
+            .spawn(move || watch(&flag))
+            .map_err(|e| tracing::warn!(error = %e, "overlay focus watcher failed to start"))
+            .ok()?;
+        Some(OverlayFocus { open })
+    }
+
+    /// Does something other than the displayed app own input right now?
+    pub fn is_open(&self) -> bool {
+        self.open.load(Ordering::Relaxed)
+    }
+}
+
+/// Gaming Mode / any gamescope session — the only place this signal exists. Mirrors the same
+/// env checks the shells already use to detect Gaming Mode.
+fn gamescope_session() -> bool {
+    std::env::var_os("GAMESCOPE_WAYLAND_DISPLAY").is_some()
+        || std::env::var_os("SteamDeck").is_some()
+        || std::env::var("XDG_CURRENT_DESKTOP").is_ok_and(|d| d.eq_ignore_ascii_case("gamescope"))
+}
+
+/// Displays worth trying, in order: ours first (a single-server gamescope publishes the atoms on
+/// the display the app is already on), then every other socket present. `/tmp/.X11-unix` is
+/// listed rather than probing `:0..:N` blindly so we never connect to a display that isn't there.
+fn candidate_displays() -> Vec<String> {
+    let mut out = Vec::new();
+    if let Ok(d) = std::env::var("DISPLAY") {
+        if !d.is_empty() {
+            out.push(d);
+        }
+    }
+    if let Ok(entries) = std::fs::read_dir("/tmp/.X11-unix") {
+        let mut found: Vec<String> = entries
+            .flatten()
+            .filter_map(|e| {
+                let name = e.file_name().into_string().ok()?;
+                let n = name.strip_prefix('X')?;
+                n.parse::<u32>().ok().map(|n| format!(":{n}"))
+            })
+            .collect();
+        found.sort();
+        for d in found {
+            if !out.contains(&d) {
+                out.push(d);
+            }
+        }
+    }
+    out
+}
+
+/// The two atoms on a root that carries them, or `None` for a display that isn't gamescope's
+/// root ctx. `only_if_exists` keeps this from interning atoms into unrelated X servers.
+fn gamescope_atoms(conn: &RustConnection) -> Option<(Atom, Atom)> {
+    let app = conn
+        .intern_atom(true, b"GAMESCOPE_FOCUSED_APP")
+        .ok()?
+        .reply()
+        .ok()?
+        .atom;
+    let gfx = conn
+        .intern_atom(true, b"GAMESCOPE_FOCUSED_APP_GFX")
+        .ok()?
+        .reply()
+        .ok()?
+        .atom;
+    (app != 0 && gfx != 0).then_some((app, gfx))
+}
+
+/// Read one CARDINAL appid. gamescope writes these with a length of ZERO when the appid is 0
+/// (`focusedAppId != 0 ? 1 : 0`), so "present but empty" is a real state meaning "no app" — it
+/// must read as `None`, not as `Some(0)` that would then compare unequal to everything.
+fn read_appid(conn: &RustConnection, root: Window, atom: Atom) -> Option<u32> {
+    let reply = conn
+        .get_property(false, root, atom, AtomEnum::CARDINAL, 0, 1)
+        .ok()?
+        .reply()
+        .ok()?;
+    // Bound rather than returned inline: the iterator borrows `reply`, and as a tail
+    // expression its temporary would outlive it.
+    let id = reply.value32()?.next();
+    id
+}
+
+/// The whole decision, separated from X so it can be tested: an overlay is up exactly when
+/// input focus and the displayed app are both known and DIFFER.
+///
+/// Absence is never an overlay. A missing value means "no app focused" (gamescope's zero-length
+/// write) or "this display stopped answering" — and a mask that latched on when the signal went
+/// away would silently kill the controller for the rest of the session, which is a far worse
+/// failure than not masking at all.
+fn overlay_open_from(app: Option<u32>, gfx: Option<u32>) -> bool {
+    matches!((app, gfx), (Some(a), Some(g)) if a != g)
+}
+
+/// True when input focus and the displayed app have diverged — an overlay is up.
+fn overlay_open(conn: &RustConnection, root: Window, app: Atom, gfx: Atom) -> bool {
+    overlay_open_from(read_appid(conn, root, app), read_appid(conn, root, gfx))
+}
+
+/// Connect, find the root ctx, then block on PropertyNotify for the two atoms. Returns on any X
+/// error so the outer loop can rebuild after a session restart.
+fn watch(flag: &Arc<AtomicBool>) {
+    loop {
+        if let Some((conn, root, app, gfx)) = connect() {
+            // Seed before the first event: the overlay may already be up when we start.
+            flag.store(overlay_open(&conn, root, app, gfx), Ordering::Relaxed);
+            loop {
+                match conn.wait_for_event() {
+                    Ok(Event::PropertyNotify(e)) if e.atom == app || e.atom == gfx => {
+                        let open = overlay_open(&conn, root, app, gfx);
+                        if flag.swap(open, Ordering::Relaxed) != open {
+                            tracing::debug!(open, "gamescope overlay focus changed");
+                        }
+                    }
+                    Ok(_) => {}
+                    Err(e) => {
+                        tracing::info!(error = %e, "gamescope focus watcher disconnected");
+                        break;
+                    }
+                }
+            }
+            // A dropped connection tells us nothing about the controller — unmask, or a
+            // gamescope restart mid-overlay would leave the pad dead with nothing to revive it.
+            flag.store(false, Ordering::Relaxed);
+        }
+        std::thread::sleep(RECONNECT_DELAY);
+    }
+}
+
+/// The first candidate display whose root carries both atoms, with PropertyNotify selected.
+fn connect() -> Option<(RustConnection, Window, Atom, Atom)> {
+    for dpy in candidate_displays() {
+        // `dpy`, not `display`: `display` is one of tracing's own value helpers, and a field
+        // named after it resolves to the helper inside the macro rather than to this string.
+        let Ok((conn, screen_num)) = RustConnection::connect(Some(&dpy)) else {
+            continue;
+        };
+        let Some((app, gfx)) = gamescope_atoms(&conn) else {
+            continue;
+        };
+        let root = conn.setup().roots[screen_num].root;
+        // Both atoms must actually be PRESENT on this root, not merely interned: a second
+        // gamescope Xwayland knows the atom names (they are per-server strings) but only the
+        // root ctx publishes the values.
+        if read_appid(&conn, root, gfx).is_none() {
+            continue;
+        }
+        // Checked rather than fire-and-forget: an event mask that silently failed to apply
+        // would leave the watcher blocked forever on a display that never speaks to it.
+        let selected = match conn.change_window_attributes(
+            root,
+            &ChangeWindowAttributesAux::new().event_mask(EventMask::PROPERTY_CHANGE),
+        ) {
+            Ok(cookie) => cookie.check().is_ok(),
+            Err(_) => false,
+        };
+        if !selected {
+            continue;
+        }
+        tracing::info!(dpy, "watching gamescope focus for overlay input masking");
+        return Some((conn, root, app, gfx));
+    }
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// The measured Deck states, both directions (2026-08-08, Steam menu and QAM alike):
+    /// equal appids while we own input, divergent while the overlay does.
+    #[test]
+    fn divergent_appids_are_an_overlay() {
+        assert!(!overlay_open_from(Some(3856846079), Some(3856846079)));
+        assert!(overlay_open_from(Some(769), Some(3856846079)));
+    }
+
+    /// gamescope writes these properties with a length of ZERO when the appid is 0, so "no app"
+    /// arrives as a missing value rather than `Some(0)`. Reading it as `Some(0)` would make it
+    /// differ from every real appid and mask the pad on an empty Gaming Mode home screen.
+    #[test]
+    fn a_missing_appid_is_never_an_overlay() {
+        assert!(!overlay_open_from(None, Some(3856846079)));
+        assert!(!overlay_open_from(Some(769), None));
+        assert!(!overlay_open_from(None, None));
+    }
+
+    /// The safety property that outranks the feature: if the signal is unreadable we forward as
+    /// before. A latched mask would leave a streaming session with a dead controller and no way
+    /// back short of restarting it.
+    #[test]
+    fn absence_fails_open_not_closed() {
+        assert!(!overlay_open_from(None, None));
+    }
+}

crates/pf-client-core/src/trust.rs

@@ -1174,12 +1174,12 @@ pub struct Settings {
     /// mirrors the Apple client's "Show game library" toggle, default off.
     pub library_enabled: bool,
     /// Which colour family the gamepad UI's living backdrop drifts through — the shared
-    /// `ui_palette` key (`"violet"` = the brand default, then `tide`/`forest`/`ember`/
-    /// `rose`/`graphite`; see `pf-console-ui`'s palette table, and the Apple/Android
-    /// clients' twins). Presentation only: nothing about a stream depends on it, which is
-    /// why it is a device preference and never part of a settings profile. An unknown
-    /// name reads as the default rather than erroring — a newer client may have shipped a
-    /// palette this binary doesn't know.
+    /// `ui_palette` key (`"violet"` = the brand default, then `oled`/`nebula`/`abyss`/
+    /// `ember`/`moss`/`graphite`, then the six pale fields; see `pf-console-ui`'s palette
+    /// table, and the Apple/Android clients' twins). Presentation only: nothing about a
+    /// stream depends on it, which is why it is a device preference and never part of a
+    /// settings profile. An unknown name reads as the default rather than erroring — a
+    /// newer client may have shipped a palette this binary doesn't know.
     #[serde(default = "default_ui_palette")]
     pub ui_palette: String,
     /// Send Wake-on-LAN before connecting to a saved host and wait for it to boot (the

crates/pf-client-core/src/video.rs

@@ -1531,6 +1531,85 @@ pub fn av1_hardware_decodable(vk: Option<&VulkanDecodeDevice>) -> bool {
     d3d11
 }
 
+/// Can this client actually DECODE 4:4:4 HEVC — the question `VIDEO_CAP_444` is a promise
+/// about, and the one nothing asked until a Steam Deck lost HEVC over it.
+///
+/// The bit used to ride the "Full chroma" toggle alone, with a comment saying the software
+/// rung was the floor underneath it. M8 removed that floor: there is no CPU HEVC decoder at
+/// all ([`software_decodable_codecs`]), and the host grants 4:4:4 only on HEVC. So on a
+/// device with no 4:4:4 decode the toggle did not cost crispness — it cost the whole codec.
+/// The Welcome resolves the chroma before a decoder exists, the native Vulkan constructor
+/// then refuses the shape, VAAPI refuses it too, and the session reconnects on H.264 with
+/// "HEVC decoding failed on this device" (field report 2026-08-08, Deck / VanGogh).
+///
+/// ⭐ Answered from the VULKAN rung alone, and that is exact rather than approximate: it is
+/// the only rung in this build that implements 4:4:4 at all. `pf_vaadec::profile_for` maps
+/// only `chroma_format_idc == 1` and errors `UnsupportedShape` on 3; `pf_dxvadec`'s config
+/// refuses "anything but 4:2:0" by construction; the CPU rung is 8-bit 4:2:0 only. So a
+/// device whose Vulkan driver offers no 4:4:4 decode profile has no 4:4:4 path in this
+/// client, whatever its silicon can do. (That is why an Intel box — whose hardware HAS done
+/// HEVC 4:4:4 since Ice Lake — is still a `false` here: our DXVA/VAAPI rungs do not
+/// implement it, so advertising it would be a lie about US, not about the GPU.)
+///
+/// ⚠ Both depths are required, not either: with HDR on, the host may resolve 4:4:4 **10-bit**,
+/// and a device offering `YUV444_8` but not `YUV444_10` would land in exactly the hole this
+/// closes. Asking for both costs one extra capability query and removes the case entirely.
+///
+/// ⚠ Deliberately NOT extended to `VIDEO_CAP_10BIT`/`VIDEO_CAP_HDR`, which are advertised
+/// unprobed for the same reason this one was. The asymmetry is real: all three hardware
+/// rungs implement 10-bit 4:2:0 (`profile_for` maps `(H265, 1, 10)` and `(Av1, 1, 10)`;
+/// pf-dxvadec carries P010), so a Vulkan-only probe there would answer `false` on boxes
+/// whose VAAPI/DXVA rung decodes 10-bit perfectly and would silently withdraw HDR from
+/// them — a visible regression bought against a case that has never been observed. Gating
+/// 10-bit honestly needs a libva/D3D11 probe, which this path cannot afford (same reason
+/// [`av1_hardware_decodable`] does not consult VAAPI).
+pub fn hevc_444_hardware_decodable(vk: Option<&VulkanDecodeDevice>) -> bool {
+    #[cfg(any(target_os = "linux", windows))]
+    {
+        vk.is_some_and(|v| {
+            crate::video_vk_native::hevc_shape_supported(v, CHROMA_444, 0)
+                && crate::video_vk_native::hevc_shape_supported(v, CHROMA_444, 2)
+        })
+    }
+    // No native Vulkan rung is compiled in off the two desktop OSes, so nothing here can
+    // decode 4:4:4 and the honest answer is a constant.
+    #[cfg(not(any(target_os = "linux", windows)))]
+    {
+        let _ = vk;
+        false
+    }
+}
+
+/// `chroma_format_idc` for 4:4:4 (H.265 7.4.3.2) — spelled once so the two depth probes
+/// above and any future caller cannot disagree about the magic number.
+const CHROMA_444: u8 = 3;
+
+/// The desktop session's `video_caps` bitfield, as a pure function of the two user
+/// switches that move it — so the rule can be tested without a GPU, a host or a Hello.
+///
+/// `want_444` is the "Full chroma" setting **already ANDed with this device's ability to
+/// decode it** ([`hevc_444_hardware_decodable`]). Split that way on purpose: the caller
+/// owns the expensive driver question and can log its own refusal with the user's setting
+/// in hand, while the bit arithmetic — the part that was wrong — stays testable.
+///
+/// `MULTI_SLICE` is unconditional and is decoder truth for THIS embedder: every desktop
+/// decode stack (Vulkan Video, D3D11VA, VAAPI, openh264/rav1d) handles AUs carrying
+/// several slice NALs, so the host may keep its multi-slice low-latency default (§7 LN1).
+/// ⚠ The mobile/TV embedders must NOT copy this blindly — Amlogic MediaCodec wedges on
+/// multi-slice AUs (see `VIDEO_CAP_MULTI_SLICE`), so they advertise per-decoder.
+///
+/// HDR off means 10-bit is not advertised either, so the host never upgrades depth.
+pub fn video_caps_for(hdr_enabled: bool, want_444: bool) -> u8 {
+    let mut caps = punktfunk_core::quic::VIDEO_CAP_MULTI_SLICE;
+    if hdr_enabled {
+        caps |= punktfunk_core::quic::VIDEO_CAP_10BIT | punktfunk_core::quic::VIDEO_CAP_HDR;
+    }
+    if want_444 {
+        caps |= punktfunk_core::quic::VIDEO_CAP_444;
+    }
+    caps
+}
+
 /// [`decodable_codecs`] plus the PyroWave bit when the presenter's device passed the
 /// compute-feature probe, minus the codecs `decoder_pref` makes unreachable.
 /// Advertisement-only: `resolve_codec` never auto-picks PyroWave — the session must also
@@ -2701,6 +2780,53 @@ mod tests {
     use super::*;
     use punktfunk_core::quic::{CODEC_AV1, CODEC_H264, CODEC_HEVC, CODEC_PYROWAVE};
 
+    /// The 4:4:4 advertisement is a PROMISE, and M8 removed the floor that used to make a
+    /// broken one survivable: there is no CPU HEVC decoder, and the host grants 4:4:4 on
+    /// HEVC only, so advertising it on a device that cannot decode it costs the entire
+    /// codec (field 2026-08-08, Steam Deck / VanGogh — HEVC fell back to H.264).
+    ///
+    /// The device question needs a GPU; THIS is the half that does not, and it is the half
+    /// that was wrong — the bit used to ride `enable_444` alone.
+    #[test]
+    fn the_444_bit_needs_the_setting_and_a_device_that_can_decode_it() {
+        const V444: u8 = punktfunk_core::quic::VIDEO_CAP_444;
+        // The regression itself: setting on, device can't → the bit must NOT go out.
+        assert_eq!(
+            video_caps_for(true, false) & V444,
+            0,
+            "a 4:4:4 promise this device cannot keep costs HEVC entirely"
+        );
+        // ...and the feature still works where it can be honoured.
+        assert_ne!(video_caps_for(true, true) & V444, 0);
+        // Never advertised unasked, whatever the device can do.
+        assert_eq!(video_caps_for(true, false) & V444, 0);
+        assert_eq!(video_caps_for(false, false) & V444, 0);
+
+        // The 4:4:4 gate must not disturb the other two bits (10-bit/HDR is deliberately
+        // NOT probe-gated — see `hevc_444_hardware_decodable`'s docs for why).
+        const HDR_BITS: u8 =
+            punktfunk_core::quic::VIDEO_CAP_10BIT | punktfunk_core::quic::VIDEO_CAP_HDR;
+        for want_444 in [false, true] {
+            assert_eq!(video_caps_for(true, want_444) & HDR_BITS, HDR_BITS);
+            assert_eq!(video_caps_for(false, want_444) & HDR_BITS, 0);
+            assert_ne!(
+                video_caps_for(false, want_444) & punktfunk_core::quic::VIDEO_CAP_MULTI_SLICE,
+                0,
+                "MULTI_SLICE is unconditional for this embedder"
+            );
+        }
+    }
+
+    /// No presenter Vulkan device ⇒ no 4:4:4, and that is an ANSWER rather than a missing
+    /// one: the native Vulkan rung is the only one in this build that implements 4:4:4 at
+    /// all (`pf_vaadec::profile_for` errors on `chroma_format_idc == 3`, pf-dxvadec refuses
+    /// anything but 4:2:0, the CPU rung is 8-bit 4:2:0). The `Some` arm needs real hardware
+    /// and lives in the GPU suites.
+    #[test]
+    fn no_vulkan_device_means_no_444_promise() {
+        assert!(!hevc_444_hardware_decodable(None));
+    }
+
     /// The reconnect rule, as the invariant it is: an exhausted codec must come back as
     /// one this client can decode ALL THE WAY DOWN, and must never come back as itself.
     ///

crates/pf-client-core/src/video_vk_native.rs

@@ -216,6 +216,70 @@ fn submit_queues_collide(graphics_qf: u32, decode_qf: u32) -> bool {
     graphics_qf == decode_qf
 }
 
+/// The queue lock this device's decode lane submits under. One function so the
+/// pre-session shape probe ([`hevc_shape_supported`]) and the real decoder cannot pick
+/// different serialization for the same device.
+fn queue_lock_for(vk: &VulkanDecodeDevice) -> Box<dyn pf_vkdecode::QueueLock> {
+    if submit_queues_collide(vk.graphics_qf, vk.decode_qf) {
+        Box::new(NativeQueueLock::Shared(vk.queue_lock.clone()))
+    } else {
+        Box::new(NativeQueueLock::Uncontended)
+    }
+}
+
+/// The presenter's handles in pf-vkdecode's shape. Same reason as [`queue_lock_for`]:
+/// the probe must ask about the DEVICE THE SESSION WOULD USE, not a re-derived one.
+fn device_handles(vk: &VulkanDecodeDevice) -> DeviceHandles {
+    DeviceHandles {
+        get_instance_proc_addr: vk.get_instance_proc_addr,
+        instance: vk.instance,
+        physical_device: vk.physical_device,
+        device: vk.device,
+        decode_qf: vk.decode_qf,
+        decode_queue_index: DECODE_QUEUE_INDEX,
+        graphics_qf: vk.graphics_qf,
+    }
+}
+
+/// Can this device hardware-decode HEVC at the given picture shape? Asked BEFORE the
+/// Hello, so the client never advertises a shape it would have to refuse a session over.
+///
+/// This is the same question, through the same code, that
+/// [`NativeVulkanDecoder::new`]'s H.265 arm asks at construction — `VkH265Decoder::new`
+/// then `probe_stream_support` — deliberately, so an advertisement and the rung that has
+/// to honour it cannot disagree. It creates and drops a decoder object; that costs a
+/// handful of driver capability queries and no session, no images and no submits.
+///
+/// `false` when the presenter has no Vulkan Video decode at all, which for 4:4:4 is the
+/// right answer rather than a missing one — see
+/// [`crate::video::hevc_444_hardware_decodable`] for why no other rung can be asked.
+pub(crate) fn hevc_shape_supported(
+    vk: &VulkanDecodeDevice,
+    chroma_format_idc: u8,
+    bit_depth_luma_minus8: u8,
+) -> bool {
+    if !vk.video_decode {
+        return false;
+    }
+    // The device-independent half first: a shape pf-vkdecode has no picture format for
+    // needs no driver to refuse it (and `probe_stream_support` would only re-derive it).
+    if pf_vkdecode::output_format_for(chroma_format_idc, bit_depth_luma_minus8).is_none() {
+        return false;
+    }
+    // SAFETY: the `DeviceHandles` contract exactly as `NativeVulkanDecoder::new` states
+    // it — these are the presenter's live instance/device, which outlive this call by
+    // construction (the presenter owns them for the whole process, and this runs on its
+    // thread while building the session's Hello). The decoder is dropped before return,
+    // so nothing outlives the borrow.
+    let dec = unsafe { pf_vkdecode::VkH265Decoder::new(&device_handles(vk), queue_lock_for(vk)) };
+    match dec {
+        Ok(d) => d
+            .probe_stream_support(chroma_format_idc, bit_depth_luma_minus8)
+            .is_ok(),
+        Err(_) => false,
+    }
+}
+
 /// [`pf_vkdecode::QueueLock`] over the device's shared [`crate::video::QueueLock`] —
 /// or over nothing, when the decode queue provably has no other submitter (see the
 /// module doc's queue-lock section).
@@ -934,21 +998,8 @@ impl NativeVulkanDecoder {
         if !vk.video_decode {
             bail!("presenter device lacks Vulkan Video decode");
         }
-        let lock: Box<dyn pf_vkdecode::QueueLock> =
-            if submit_queues_collide(vk.graphics_qf, vk.decode_qf) {
-                Box::new(NativeQueueLock::Shared(vk.queue_lock.clone()))
-            } else {
-                Box::new(NativeQueueLock::Uncontended)
-            };
-        let handles = DeviceHandles {
-            get_instance_proc_addr: vk.get_instance_proc_addr,
-            instance: vk.instance,
-            physical_device: vk.physical_device,
-            device: vk.device,
-            decode_qf: vk.decode_qf,
-            decode_queue_index: DECODE_QUEUE_INDEX,
-            graphics_qf: vk.graphics_qf,
-        };
+        let lock = queue_lock_for(vk);
+        let handles = device_handles(vk);
         // The `DeviceHandles` caller contract, held for the decoder's whole lifetime
         // and identical for both arms (it is the HANDLES' contract, not the codec's):
         // the handles are the presenter's live instance/device, which outlives every

crates/pf-console-ui/src/library.rs

@@ -246,17 +246,34 @@ const CELL_RAMP: [f64; 16] = [
     -0.10,  0.08, -0.06,  0.12,
 ];
 
-/// The twelve shipped palettes: the brand default, five more dark fields, then six pale ones.
+/// The thirteen shipped palettes: the brand default, six more dark fields, then six pale ones.
 /// Cycling order runs dark → light, so stepping the row walks the whole range in one direction.
 /// Adding one here adds it to every console settings screen; the Apple and Android tables must
 /// gain the same entry to keep the `ui_palette` key portable.
 #[rustfmt::skip]
-pub const PALETTES: [Palette; 12] = [
+pub const PALETTES: [Palette; 13] = [
     // --- dark fields (white ink) ---
     Palette {
         id: "violet", name: "Violet", stops: None,
         ground: (0.075, 0.060, 0.160), accent: (0.525, 0.471, 0.961), light: false,
     },
+    Palette {
+        // For OLED and AMOLED panels, where a black pixel is a pixel switched off — no glow,
+        // no power. The ramp's first two stops are literally (0,0,0), so the whole shaded half
+        // of the field is genuinely off rather than "very dark grey", and the ground is pure
+        // black too: the calm mix on the form screens lifts toward nothing, so settings and
+        // pairing sit on an unlit panel. What is left is a faint indigo→violet ember in the
+        // bright corner, dim enough to stay under a tenth of the other dark fields' mean
+        // luminance while keeping the backdrop a field with somewhere to go rather than a
+        // dead rectangle. The accent stays the brand violet — focus has to be findable on
+        // black.
+        id: "oled", name: "OLED",
+        stops: Some(&[
+            (0.000, 0.000, 0.000), (0.000, 0.000, 0.000), (0.010, 0.020, 0.100),
+            (0.045, 0.016, 0.115), (0.120, 0.024, 0.130),
+        ]),
+        ground: (0.0, 0.0, 0.0), accent: (0.525, 0.471, 0.961), light: false,
+    },
     Palette {
         // Deep indigo climbing through violet into a hot magenta.
         id: "nebula", name: "Nebula",
@@ -857,7 +874,7 @@ mod tests {
         assert_eq!(
             ids,
             [
-                "violet", "nebula", "abyss", "ember", "moss", "graphite", "holo", "sunset",
+                "violet", "oled", "nebula", "abyss", "ember", "moss", "graphite", "holo", "sunset",
                 "bloom", "dawn", "mint", "opal",
             ]
         );
@@ -867,7 +884,36 @@ mod tests {
             .position(|p| p.light)
             .expect("some are light");
         assert!(PALETTES[first_light..].iter().all(|p| p.light));
-        assert_eq!(first_light, 6);
+        assert_eq!(first_light, 7);
+    }
+
+    /// OLED is the one palette whose selling point is measurable: it has to be genuinely
+    /// black, not merely the darkest of the dark fields. Pure black corners, a mean well
+    /// under every other field's, and a ground that lifts to nothing on the form screens.
+    #[test]
+    fn oled_is_actually_black() {
+        let luma = |c: (f64, f64, f64)| 0.2126 * c.0 + 0.7152 * c.1 + 0.0722 * c.2;
+        let oled = palette("oled");
+        assert_eq!(
+            oled.ground,
+            (0.0, 0.0, 0.0),
+            "the calm lift must be nothing"
+        );
+        let cells = oled.mesh_colors();
+        assert!(
+            cells.iter().filter(|c| luma(**c) == 0.0).count() >= 3,
+            "the shaded corner has to be switched off, not dimmed"
+        );
+        let mean = cells.iter().map(|c| luma(*c)).sum::<f64>() / 16.0;
+        let darkest_other = PALETTES
+            .iter()
+            .filter(|p| p.id != "oled")
+            .map(|p| p.mesh_colors().iter().map(|c| luma(*c)).sum::<f64>() / 16.0)
+            .fold(f64::MAX, f64::min);
+        assert!(
+            mean < darkest_other / 2.0,
+            "oled means {mean:.3}, only half a stop under {darkest_other:.3}"
+        );
     }
 
     /// Every colour a palette produces stays in gamut, and a pale palette really is pale —

crates/pf-console-ui/src/screens/settings.rs

@@ -258,11 +258,17 @@ impl SettingsScreen {
         }
     }
 
-    /// The rows of the CURRENT tab. Profiles is built from the catalog: one row per
-    /// profile, or the explainer placeholder while there are none.
-    fn row_ids(&self) -> Vec<RowId> {
+    /// The rows of the CURRENT tab, minus any whose setting has nothing to act on (see
+    /// [`row_applies`]). Profiles is built from the catalog: one row per profile, or the
+    /// explainer placeholder while there are none.
+    fn row_ids(&self, ctx: &Ctx) -> Vec<RowId> {
         if self.tab != PROFILES_TAB {
-            return TABS[self.tab].1.to_vec();
+            return TABS[self.tab]
+                .1
+                .iter()
+                .copied()
+                .filter(|id| row_applies(*id, ctx.settings))
+                .collect();
         }
         if self.profiles.is_empty() {
             vec![RowId::NoProfiles]
@@ -271,6 +277,16 @@ impl SettingsScreen {
         }
     }
 
+    /// Pull the cursor back onto the list. Every tab but Profiles used to be a fixed length,
+    /// so this only mattered on entry ([`show_tab`]); the smoothness buffer's row now comes
+    /// and goes, and another writer (a desktop shell, a session's match-window persist) can
+    /// take it away between frames while this screen is open.
+    fn clamp_cursor(&mut self, len: usize) {
+        if self.list.cursor >= len {
+            self.list.jump_to(len.saturating_sub(1));
+        }
+    }
+
     #[cfg(test)]
     pub(crate) fn tab_for_test(&self) -> usize {
         self.tab
@@ -278,21 +294,22 @@ impl SettingsScreen {
 
     /// L1/R1 (and Tab/PgUp/PgDn) — move one tab, wrapping (the strip is a ring, like A's
     /// value cycle), keeping each tab's own cursor.
-    fn switch_tab(&mut self, delta: i32) -> Option<MenuPulse> {
+    fn switch_tab(&mut self, delta: i32, ctx: &Ctx) -> Option<MenuPulse> {
         let n = TABS.len() as i32;
-        self.show_tab((self.tab as i32 + delta).rem_euclid(n) as usize)
+        self.show_tab((self.tab as i32 + delta).rem_euclid(n) as usize, ctx)
     }
 
     /// Show `tab`, parking the cursor the outgoing tab was on. Also the pointer's path in:
     /// a press on a pill names a tab outright rather than a direction to step in.
-    fn show_tab(&mut self, tab: usize) -> Option<MenuPulse> {
+    fn show_tab(&mut self, tab: usize, ctx: &Ctx) -> Option<MenuPulse> {
         if tab >= TABS.len() {
             return None;
         }
         self.tab_cursors[self.tab] = self.list.cursor;
         self.tab = tab;
-        // Clamp the remembered cursor: the Profiles tab's length follows the catalog.
-        let len = self.row_ids().len();
+        // Clamp the remembered cursor: the Profiles tab's length follows the catalog, and
+        // Video's follows whether the smoothness buffer is offered.
+        let len = self.row_ids(ctx).len();
         self.list
             .jump_to(self.tab_cursors[self.tab].min(len.saturating_sub(1)));
         Some(MenuPulse::Move)
@@ -302,10 +319,11 @@ impl SettingsScreen {
     /// there is never meant for a row.
     pub(crate) fn pointer(&mut self, p: Pointer, ctx: &mut Ctx, fx: &mut Outbox) -> bool {
         if let Some(tab) = self.strip.pointer(p) {
-            self.show_tab(tab);
+            self.show_tab(tab, ctx);
             return true;
         }
-        let ids = self.row_ids();
+        let ids = self.row_ids(ctx);
+        self.clamp_cursor(ids.len());
         let (msg, pulse) = self.list.pointer(p, ids.len());
         if matches!(msg, ListMsg::None) && pulse.is_none() {
             return false;
@@ -325,11 +343,12 @@ impl SettingsScreen {
                 fx.pop();
                 return None;
             }
-            MenuEvent::JumpBack => return self.switch_tab(-1),
-            MenuEvent::JumpForward => return self.switch_tab(1),
+            MenuEvent::JumpBack => return self.switch_tab(-1, ctx),
+            MenuEvent::JumpForward => return self.switch_tab(1, ctx),
             _ => {}
         }
-        let ids = self.row_ids();
+        let ids = self.row_ids(ctx);
+        self.clamp_cursor(ids.len());
         let (msg, pulse) = self.list.menu(ev, ids.len());
         self.apply_row(msg, pulse, &ids, ctx, fx)
     }
@@ -344,8 +363,14 @@ impl SettingsScreen {
         ctx: &mut Ctx,
         fx: &mut Outbox,
     ) -> Option<MenuPulse> {
+        // A cursor with no row under it can only mean the list shrank between the clamp above
+        // and here, which nothing does today — but indexing on the assumption would turn that
+        // into a panic in a shipping console rather than a dropped keypress.
+        let Some(&focused) = ids.get(self.list.cursor) else {
+            return pulse;
+        };
         // The Profiles rows navigate instead of editing the settings file.
-        match ids[self.list.cursor] {
+        match focused {
             RowId::Profile(i) => {
                 return match msg {
                     ListMsg::Activate => {
@@ -378,7 +403,7 @@ impl SettingsScreen {
         }
         match msg {
             ListMsg::Adjust(delta) => {
-                let changed = adjust(ids[self.list.cursor], delta, false, ctx);
+                let changed = adjust(focused, delta, false, ctx);
                 if changed {
                     ctx.settings.save();
                     Some(MenuPulse::Move)
@@ -388,7 +413,7 @@ impl SettingsScreen {
             }
             ListMsg::Activate => {
                 // A cycles forward WRAPPING, so every option is reachable one-handed.
-                if adjust(ids[self.list.cursor], 1, true, ctx) {
+                if adjust(focused, 1, true, ctx) {
                     ctx.settings.save();
                 }
                 pulse
@@ -397,8 +422,8 @@ impl SettingsScreen {
         }
     }
 
-    pub(crate) fn hints(&self, _ctx: &Ctx) -> Vec<Hint> {
-        let ids = self.row_ids();
+    pub(crate) fn hints(&self, ctx: &Ctx) -> Vec<Hint> {
+        let ids = self.row_ids(ctx);
         // The shoulders always change section, so that hint leads on every row.
         let mut hints = vec![Hint::new(HintKey::Shoulders, "Section")];
         hints.extend(match ids.get(self.list.cursor) {
@@ -445,7 +470,8 @@ impl SettingsScreen {
             rect.right,
             rect.bottom - detail_h as f32,
         );
-        let ids = self.row_ids();
+        let ids = self.row_ids(ctx);
+        self.clamp_cursor(ids.len());
         let rows: Vec<RowSpec> = ids
             .iter()
             .map(|id| row_spec(*id, ctx, &self.profiles))
@@ -466,6 +492,24 @@ impl SettingsScreen {
     }
 }
 
+/// Whether a row is OFFERED at all, as opposed to offered-but-inert.
+///
+/// The two are a real distinction. Echo cancellation and the pad rows follow a switch the user
+/// can see a line or two above them, so dimming them shows the relationship — dropping them
+/// would just make settings appear and disappear as the switch flips. The smoothness buffer is
+/// different: it is not a sub-setting of a switch, it is a knob on ONE of two intents, and
+/// under Lowest latency it names a quantity that doesn't exist. Every other settings surface —
+/// the GTK and WinUI shells, the Apple touch/tvOS screens, the Android touch screen — hides it
+/// there. This screen was the lone exception because its row list was fixed; it is rebuilt from
+/// this filter each frame now, and the row it drops sits directly BELOW the row that drops it,
+/// so the cursor is never under anything that moves.
+fn row_applies(id: RowId, s: &pf_client_core::trust::Settings) -> bool {
+    match id {
+        RowId::SmoothBuffer => s.present_priority == "smooth",
+        _ => true,
+    }
+}
+
 fn row_spec(id: RowId, ctx: &Ctx, profiles: &[(String, String)]) -> RowSpec {
     // The Profiles section: name + how many hosts pin it (counted from the live rows, so
     // it reflects what the carousel shows). Read-only here beyond opening the pin screen.
@@ -497,18 +541,17 @@ fn row_spec(id: RowId, ctx: &Ctx, profiles: &[(String, String)]) -> RowSpec {
         _ => {}
     }
     let s = &ctx.settings;
-    // Several rows follow another: echo cancellation only means anything while the mic
-    // streams, the pad rows only while any controller is forwarded at all, and the
-    // smoothness buffer only while that intent is chosen. All go dim and inert otherwise
-    // — the same relationship the desktop shells draw by greying a row out (they hide the
-    // buffer row entirely; a fixed row list can't, and a row that vanished mid-list would
-    // move everything under the cursor).
+    // Two rows follow a switch a line or two above them: echo cancellation only means
+    // anything while the mic streams, and the pad rows only while any controller is
+    // forwarded at all. Both go dim and inert otherwise — the same relationship the desktop
+    // shells draw by greying a row out, and dimming (not dropping) is what shows the
+    // relationship. The smoothness buffer used to be listed here too; it is dropped from the
+    // list instead now — see [`row_applies`] for why that one is different.
     let enabled = match id {
         RowId::EchoCancel => s.mic_enabled,
         RowId::Pad | RowId::PadType | RowId::SystemButtons | RowId::GuideGesture => {
             s.gamepad_forwarding
         }
-        RowId::SmoothBuffer => s.present_priority == "smooth",
         _ => true,
     };
     let (header, label, value): (Option<&'static str>, &str, String) = match id {
@@ -848,7 +891,10 @@ fn adjust(id: RowId, delta: i32, wrap: bool, ctx: &mut Ctx) -> bool {
             step_option(cur, PRESENT_PRIORITIES.len(), delta, wrap)
                 .map(|i| s.present_priority = PRESENT_PRIORITIES[i].0.to_string())
         }
-        // Inert unless smoothness is chosen — a boundary thud, matching the dimmed row.
+        // Under Lowest latency the row isn't offered at all ([`row_applies`]), so this branch
+        // is only reachable if another writer flipped the intent between the frame that built
+        // the list and the keypress that lands here — a boundary thud, not a stored value
+        // nothing will read.
         RowId::SmoothBuffer => {
             if s.present_priority == "smooth" {
                 let cur = SMOOTH_BUFFERS
@@ -1093,9 +1139,6 @@ mod tests {
         fake_home();
         let mut s = SettingsScreen::with_profiles(Vec::new());
         rendered(&mut s);
-        // Row 0 of the leading tab is Resolution, whose first step is Native → Match
-        // window: one field, one unambiguous effect to assert on.
-        assert_eq!(s.row_ids()[0], RowId::Resolution);
         let first = s.list.row_rect(0).expect("the list drew its rows");
         let (mut settings, pads) = ctx_parts();
         settings.save(); // seat the fake HOME's file — `apply_row` rebases on it
@@ -1109,6 +1152,9 @@ mod tests {
             device_name: "t",
             t: 0.0,
         };
+        // Row 0 of the leading tab is Resolution, whose first step is Native → Match
+        // window: one field, one unambiguous effect to assert on.
+        assert_eq!(s.row_ids(&ctx)[0], RowId::Resolution);
         let mut fx = Outbox::default();
         assert!(!ctx.settings.match_window);
         assert!(s.pointer(press(first), &mut ctx, &mut fx));
@@ -1232,13 +1278,12 @@ mod tests {
         assert!(ctx.settings.echo_cancel);
     }
 
-    /// The smoothness buffer follows the presentation intent, exactly as echo cancellation
-    /// follows the mic: dimmed and inert under Lowest latency (where holding frames means
-    /// nothing), live under Smoothness. The desktop shells hide the row instead; a fixed
-    /// row list dims it, because a row vanishing mid-list would shift everything under the
-    /// cursor.
+    /// The smoothness buffer is OFFERED only under Smoothness — under Lowest latency it names
+    /// a quantity that doesn't exist, so the row is gone from the Video tab rather than sitting
+    /// there dimmed. This is what the GTK and WinUI shells and the Apple/Android screens have
+    /// always done; this screen was the exception until its row list stopped being fixed.
     #[test]
-    fn smoothness_buffer_follows_the_intent() {
+    fn smoothness_buffer_is_offered_only_under_smoothness() {
         let (mut settings, pads) = ctx_parts();
         assert_eq!(settings.present_priority, "latency", "the shipped default");
         let library = crate::library::LibraryShared::default();
@@ -1251,24 +1296,93 @@ mod tests {
             device_name: "t",
             t: 0.0,
         };
-        assert!(!row_spec(RowId::SmoothBuffer, &ctx, &[]).enabled);
+        let mut s = SettingsScreen::with_profiles(Vec::new());
+        s.tab = TABS
+            .iter()
+            .position(|(name, _)| *name == "Video")
+            .expect("the Video tab");
+
+        let video = s.row_ids(&ctx);
+        assert!(
+            !video.contains(&RowId::SmoothBuffer),
+            "latency hides the buffer row: {video:?}"
+        );
+        assert!(video.contains(&RowId::PresentPriority), "the intent stays");
+        // Even reached out of band it writes nothing — the list it came from is a frame old.
         assert!(
             !adjust(RowId::SmoothBuffer, 1, false, &mut ctx),
             "latency intent = thud"
         );
         assert_eq!(ctx.settings.smooth_buffer, 0, "and nothing was written");
 
-        // Stepping the intent to Smoothness brings the buffer row to life.
+        // Stepping the intent to Smoothness brings the row into the list, directly under it.
         assert!(adjust(RowId::PresentPriority, 1, false, &mut ctx));
         assert_eq!(ctx.settings.present_priority, "smooth");
-        assert!(row_spec(RowId::SmoothBuffer, &ctx, &[]).enabled);
+        let video = s.row_ids(&ctx);
+        let intent = video
+            .iter()
+            .position(|id| *id == RowId::PresentPriority)
+            .expect("the intent row");
+        assert_eq!(
+            video.get(intent + 1),
+            Some(&RowId::SmoothBuffer),
+            "the row that comes and goes sits BELOW the row that decides it, so the cursor \
+             never has anything move out from under it"
+        );
         assert!(adjust(RowId::SmoothBuffer, 1, false, &mut ctx));
         assert_eq!(ctx.settings.smooth_buffer, 1);
 
-        // The intent wraps back and the row goes inert again.
+        // The intent wraps back and the row leaves again — with the cursor parked on the
+        // intent row, which is where a user who just stepped it necessarily is.
+        s.list.cursor = intent;
         assert!(adjust(RowId::PresentPriority, -1, false, &mut ctx));
         assert_eq!(ctx.settings.present_priority, "latency");
-        assert!(!row_spec(RowId::SmoothBuffer, &ctx, &[]).enabled);
+        let video = s.row_ids(&ctx);
+        assert!(!video.contains(&RowId::SmoothBuffer));
+        assert_eq!(
+            video.get(s.list.cursor),
+            Some(&RowId::PresentPriority),
+            "the cursor is still on the row the user was stepping"
+        );
+    }
+
+    /// A cursor parked past the end of a list that shrank underneath it is pulled back rather
+    /// than indexed with — the console must not panic because another writer changed the
+    /// presentation intent while its settings screen was open.
+    #[test]
+    fn a_shrinking_list_pulls_the_cursor_back() {
+        // `apply_row` rebases on the FILE before acting, so this has to be seated — and
+        // seated with the SHRUNKEN list's intent, which is the state being tested.
+        fake_home();
+        let (mut settings, pads) = ctx_parts();
+        settings.present_priority = "latency".into();
+        settings.save();
+        settings.present_priority = "smooth".into();
+        let library = crate::library::LibraryShared::default();
+        let mut ctx = Ctx {
+            hosts: &[],
+            library: &library,
+            settings: &mut settings,
+            pads: &pads,
+            deck: false,
+            device_name: "t",
+            t: 0.0,
+        };
+        let mut s = SettingsScreen::with_profiles(Vec::new());
+        s.tab = TABS
+            .iter()
+            .position(|(name, _)| *name == "Video")
+            .expect("the Video tab");
+        // Park on the last row while the buffer row is still there…
+        s.list.cursor = s.row_ids(&ctx).len() - 1;
+        let parked = s.list.cursor;
+        // …then take it away behind the screen's back, as a desktop shell would.
+        ctx.settings.present_priority = "latency".into();
+        let mut fx = Outbox::default();
+        let pulse = s.menu(MenuEvent::Confirm, &mut ctx, &mut fx);
+        assert!(pulse.is_some(), "the press was routed, not dropped");
+        assert!(s.list.cursor < parked, "the cursor came back onto the list");
+        assert!(fx.nav.is_none());
     }
 
     #[test]
@@ -1392,7 +1506,7 @@ mod tests {
             ("p2".into(), "Game".into()),
         ]);
         s.tab = PROFILES_TAB;
-        let ids = s.row_ids();
+        let ids = s.row_ids(&ctx);
         assert_eq!(ids, vec![RowId::Profile(0), RowId::Profile(1)]);
 
         let spec = row_spec(RowId::Profile(0), &ctx, &s.profiles);
@@ -1438,7 +1552,7 @@ mod tests {
         };
         let mut s = SettingsScreen::with_profiles(Vec::new());
         s.tab = PROFILES_TAB;
-        let ids = s.row_ids();
+        let ids = s.row_ids(&ctx);
         assert_eq!(ids, vec![RowId::NoProfiles]);
         let spec = row_spec(RowId::NoProfiles, &ctx, &s.profiles);
         assert!(!spec.enabled);

crates/pf-console-ui/src/shell/tests.rs

@@ -329,7 +329,7 @@ fn dump_console_screens() {
     for _ in 0..5 {
         s.handle_menu(MenuEvent::JumpForward);
     }
-    for id in ["violet", "ember", "abyss", "holo", "sunset", "mint"] {
+    for id in ["violet", "oled", "ember", "abyss", "holo", "sunset", "mint"] {
         s.settings.ui_palette = id.to_string();
         dump(&mut s, 40, 8, &format!("03-settings-{id}"), true);
     }

crates/pf-encode/src/enc/pyrowave_wire.rs

@@ -53,6 +53,32 @@ pub(crate) fn stamp_color_bits(bitstream: &mut [u8], seq_offset: usize, bt2020_p
     }
 }
 
+/// Read the 3-bit wire sequence counter out of a pyrowave block header.
+///
+/// Every block header is `{ u16 ballot; u16 payload_words:12, sequence:3, extended:1; u32 ... }`
+/// (`pyrowave_common.hpp`, `static_assert(sizeof == 8)`), so the counter is bits 12..14 of the
+/// little-endian half-word at `packet_offset + 2` — the same word `stamp_color_bits` reaches into
+/// from the other end.
+///
+/// This field is the entire frame-boundary signal on the wire: the decoder restarts a frame only
+/// when the value CHANGES (`diff = (hdr.sequence - last_seq) & 0x7; restart = diff != 0`), so a
+/// repeated value is read as more blocks of the same frame. That is why PW5's alternating encoder
+/// handles need `pyrowave_encoder_set_next_sequence`, and why a test asserts this reader sees
+/// +1 mod 8 across the pair.
+///
+/// Its only caller is the Linux backend — alternating encoder handles are a Linux-side concern, and
+/// the Windows backend drives pyrowave's compat device with a single handle. The rest of this module
+/// really is shared (`packet_boundary` and `stamp_color_bits` have callers on both), so the exemption
+/// is scoped to this one item rather than the file: `dead_code` stays live on Linux, where the caller
+/// lives and where its disappearing would be a real finding. Windows builds with `-D warnings`, so
+/// without this the host and tray clippy legs fail to compile the lib at all.
+#[cfg_attr(not(target_os = "linux"), allow(dead_code))]
+pub(crate) fn wire_sequence(bitstream: &[u8], packet_offset: usize) -> Option<u8> {
+    let lo = *bitstream.get(packet_offset + 2)?;
+    let hi = *bitstream.get(packet_offset + 3)?;
+    Some(((u16::from_le_bytes([lo, hi]) >> 12) & 0x7) as u8)
+}
+
 /// The wavelet block space's total 32x32-block count for a mode — the exact counting walk of
 /// upstream `WaveletBuffers::init_block_meta` (also ported to the Apple `WaveletLayout`, whose
 /// golden tests pin it against real host AUs). Needed because the vendored RDO pass packs the
@@ -201,6 +227,193 @@ pub(crate) fn build_au(
     au
 }
 
+// ---------------------------------------------------------------------------
+// Streamed-AU chunk cutting (PW6 — latency plan §T3.4, wave-2 plan PW6)
+// ---------------------------------------------------------------------------
+
+/// Default per-chunk target — ~3–4 chunks for a 400 Mb/s 60 fps AU (~833 KB). Deliberately coarse,
+/// because the SEALER, not this size, sets how early bytes actually leave:
+///
+/// * Toward a plain `VIDEO_CAP_STREAMED_AU` client, `Packetizer::push_streamed` flushes only when
+///   its pending buffer exceeds one FEC block — `fec.max_data_per_block × shard_payload`, which is
+///   200 × 1408 = 281 600 B on the shipped 1500-MTU IPv4 geometry. Anything smaller than that is
+///   simply buffered. (256 KiB sits just under one block, so the first flush lands on the SECOND
+///   chunk; the win is intact either way — the whole-AU path seals all ~3 blocks before its first
+///   datagram may leave.) Only a client that ALSO negotiated `VIDEO_CAP_MULTI_SLICE` gets the
+///   finer `MIN_STREAM_BLOCK_SHARDS` floor (16 shards ≈ 22 KB), where the chunk size does set the
+///   flush granularity directly. pf-encode is not told the session's FEC geometry, so this is a
+///   fixed byte target rather than a block-derived one.
+/// * Chunks are not free: the send thread paces each sealed batch on its own
+///   (`stream.rs::pace_sealed`), and every call grants a fresh `max(bytes/4, 128 KiB)` microburst
+///   allowance. Cutting an AU into dozens of chunks therefore erodes the pacing this host does to
+///   stop line-rate bursts from overrunning the NIC — the failure mode the pacer exists for.
+const STREAM_CHUNK_TARGET_BYTES: usize = 256 * 1024;
+/// Clamp on the `PUNKTFUNK_PYROWAVE_CHUNK_KIB` override (see [`stream_chunk_step`]).
+const STREAM_CHUNK_MIN_KIB: usize = 4;
+const STREAM_CHUNK_MAX_KIB: usize = 8192;
+
+/// Whether streamed-AU output is armed for this host process.
+///
+/// **Default OFF, and deliberately so.** The streamed wire shape costs one PyroWave-specific
+/// regression that has not been measured: an UNPINNED streamed frame (its final block never
+/// arrived, so `frame_bytes` is still the 0 sentinel) is excluded from partial delivery
+/// (`reassemble.rs`, 2026-07 security-review finding 10) — where today's whole-AU path hands the
+/// consumer a usable blurred partial, a streamed frame that loses its final block delivers
+/// NOTHING. PyroWave clients opt into partial delivery unconditionally
+/// (`client/pump/handshake.rs`), so this is a live behaviour change for every one of them. The
+/// netem loss-harness leg (2 % on `lo`, FEC pinned off — the Phase-4 recipe) comparing
+/// partial-delivery rates streamed vs whole-AU is the prerequisite for flipping the default;
+/// until it has run, `PUNKTFUNK_PYROWAVE_STREAMED_AU=1` is how you get it.
+///
+/// The client's `VIDEO_CAP_STREAMED_AU` and the host's `PUNKTFUNK_STREAMED_AU` remain the outer
+/// gates (`stream.rs`) — this only decides whether the ENCODER offers chunks at all.
+fn stream_armed() -> bool {
+    static ARMED: std::sync::OnceLock<bool> = std::sync::OnceLock::new();
+    // Latched once: `supports_chunked_poll` is re-queried per AU, and a knob that could change
+    // mid-session would flip the wire shape under an open `StreamedAu`.
+    *ARMED.get_or_init(|| {
+        matches!(
+            std::env::var("PUNKTFUNK_PYROWAVE_STREAMED_AU").as_deref(),
+            Ok("1")
+        )
+    })
+}
+
+/// Bytes per streamed chunk, rounded DOWN to a whole number of `window`-sized windows (never
+/// below one). The rounding is the whole point — see [`AuChunker`].
+fn chunk_step(window: usize, target: usize) -> usize {
+    (target / window.max(1)).max(1) * window.max(1)
+}
+
+/// The streamed-AU chunk size for a backend whose wire chunking is `wire_chunk`, or `None` when
+/// this session must stay on the whole-AU path — which is the answer whenever the feature is not
+/// armed ([`stream_armed`]) or the encoder is in DENSE mode.
+///
+/// Dense mode is excluded on purpose: there the AU is ONE atomic pyrowave packet with no window
+/// framing, so a cut is neither shard-aligned nor a framing boundary. Every real PyroWave session
+/// runs datagram-aligned (`stream.rs` sets `plan.wire_chunk = Some(session.shard_payload())`), so
+/// nothing is lost — but the invariant this file promises stays true instead of nearly true.
+///
+/// `PUNKTFUNK_PYROWAVE_CHUNK_KIB` overrides the target (clamped to
+/// [`STREAM_CHUNK_MIN_KIB`]..=[`STREAM_CHUNK_MAX_KIB`]); garbage falls back to the default.
+pub(crate) fn stream_chunk_step(wire_chunk: Option<usize>) -> Option<usize> {
+    let window = wire_chunk.filter(|&w| w > 0)?;
+    if !stream_armed() {
+        return None;
+    }
+    static TARGET: std::sync::OnceLock<usize> = std::sync::OnceLock::new();
+    let target = *TARGET.get_or_init(|| {
+        std::env::var("PUNKTFUNK_PYROWAVE_CHUNK_KIB")
+            .ok()
+            .and_then(|v| v.trim().parse::<usize>().ok())
+            .filter(|k| (STREAM_CHUNK_MIN_KIB..=STREAM_CHUNK_MAX_KIB).contains(k))
+            .map(|k| k * 1024)
+            .unwrap_or(STREAM_CHUNK_TARGET_BYTES)
+    });
+    Some(chunk_step(window, target))
+}
+
+/// Hands a **finished** datagram-aligned AU out in window-aligned pieces for the streamed-AU wire
+/// ([`crate::Encoder::poll_chunk`], `punktfunk_core::quic::VIDEO_CAP_STREAMED_AU`). Shared by both
+/// pyrowave backends so the cut rule cannot drift between Linux and Windows — the Windows backend
+/// cannot even be compiled from a Linux/macOS dev box, so logic written into it directly ships
+/// unverified.
+///
+/// ## What this does NOT buy (read before quoting PW6 as a latency win)
+///
+/// pyrowave's `encode_frame` is **synchronous**: `submit` returns only once the whole AU sits in
+/// `pending`, so by the time the host can poll a chunk the encode is over. `poll_chunk` is
+/// therefore NOT "emit slices as the encoder produces them" — it is "hand the finished AU out in
+/// pieces so the wire work pipelines with itself". Concretely, what moves:
+///
+/// * whole-AU path: `Session::seal_frame_at` FEC-protects, packetizes and AEAD-seals the ENTIRE
+///   ~830 KB AU before its first datagram may leave the socket;
+/// * streamed path: each FEC block seals and paces as it completes, so the first byte reaches the
+///   wire after one block's seal, and the remaining seal work overlaps its own transmission.
+///
+/// There is NO encode/send overlap here — unlike the H.26x sub-frame slice path, where chunks
+/// genuinely appear while the encoder is still working. PW6 and PW5 (encode overlap) are
+/// independent packages, not sequential ones.
+///
+/// It also does **not** give the client decode-while-arriving: the reassembler completes a
+/// streamed AU exactly like a whole one (`reassemble.rs` — `block_count != 0 && blocks_ok ==
+/// block_count`) and hands up ONE `Frame`. Client-side prefix decode is the separate
+/// `Session::set_deliver_frame_parts` opt-in, which PyroWave's newest-wins frame channel cannot
+/// take — see the PW6 section of `design/linux-host-performance-wave2-pyrowave.md`.
+///
+/// ## The cut rule
+///
+/// A chunk is a whole number of `chunk`-sized WINDOWS. [`build_au`] gives every window exactly ONE
+/// `kind` in its 4-byte prefix (`WIN_PACKED` or one link of a `WIN_FRAG_*` chain), so a cut inside
+/// a window would split a unit the clients parse atomically. Whole windows are `shard_payload`
+/// multiples by construction, which is what makes the sealer's sentinel block bases shard-aligned
+/// for free (plan §4.4) — the streamed path's placement contract.
+pub(crate) struct AuChunker {
+    au: Vec<u8>,
+    /// Bytes already handed out.
+    cursor: usize,
+    /// Bytes per chunk — a whole number of windows ([`chunk_step`]).
+    step: usize,
+    pts_ns: u64,
+    keyframe: bool,
+    recovery_anchor: bool,
+    chunk_aligned: bool,
+    /// Set once anything has been emitted, so the degenerate EMPTY AU still owes exactly one
+    /// chunk and not an infinite stream of them.
+    emitted: bool,
+}
+
+impl AuChunker {
+    pub(crate) fn new(frame: crate::EncodedFrame, step: usize) -> AuChunker {
+        AuChunker {
+            au: frame.data,
+            cursor: 0,
+            step: step.max(1),
+            pts_ns: frame.pts_ns,
+            keyframe: frame.keyframe,
+            recovery_anchor: frame.recovery_anchor,
+            chunk_aligned: frame.chunk_aligned,
+            emitted: false,
+        }
+    }
+
+    /// The next piece, or `None` once the AU is spent. The pieces concatenate to exactly the bytes
+    /// [`crate::Encoder::poll`] would have returned; `first` opens the wire frame and `last` closes
+    /// it (the host's `handle_chunk` keys its `begin`/`finish` off precisely those two).
+    pub(crate) fn next(&mut self) -> Option<crate::AuChunk> {
+        if self.cursor >= self.au.len() {
+            // A zero-byte AU is not reachable through `build_au` (it always emits at least one
+            // window), but the host would leak its open `StreamedAu` if a chunked poll returned
+            // nothing at all — so the degenerate case still owes one self-closing chunk.
+            if self.emitted {
+                return None;
+            }
+            self.emitted = true;
+            return Some(self.chunk(Vec::new(), true, true));
+        }
+        let first = self.cursor == 0;
+        let end = (self.cursor + self.step).min(self.au.len());
+        let data = self.au[self.cursor..end].to_vec();
+        self.cursor = end;
+        self.emitted = true;
+        Some(self.chunk(data, first, end == self.au.len()))
+    }
+
+    /// AU-level metadata rides every chunk (the `AuChunk` contract only makes it authoritative on
+    /// `first`, but a truthful copy on each one costs nothing and keeps a mid-AU log honest).
+    fn chunk(&self, data: Vec<u8>, first: bool, last: bool) -> crate::AuChunk {
+        crate::AuChunk {
+            data,
+            pts_ns: self.pts_ns,
+            keyframe: self.keyframe,
+            recovery_anchor: self.recovery_anchor,
+            chunk_aligned: self.chunk_aligned,
+            first,
+            last,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -362,4 +575,119 @@ mod tests {
         stamp_color_bits(&mut bs, 0, true);
         assert_eq!(bs[7], 0x78);
     }
+
+    // --- streamed-AU chunk cutting (PW6) ------------------------------------
+    // Appended at module END per the wave plan's ownership rule.
+
+    fn frame(data: Vec<u8>) -> crate::EncodedFrame {
+        crate::EncodedFrame {
+            data,
+            pts_ns: 1_234_567,
+            keyframe: true,
+            recovery_anchor: false,
+            chunk_aligned: true,
+        }
+    }
+
+    /// Drain a chunker into `(concatenated bytes, per-chunk lengths, first flags, last flags)`.
+    fn drain(mut c: AuChunker) -> (Vec<u8>, Vec<usize>, Vec<bool>, Vec<bool>) {
+        let (mut bytes, mut lens, mut firsts, mut lasts) = (Vec::new(), Vec::new(), vec![], vec![]);
+        while let Some(ch) = c.next() {
+            lens.push(ch.data.len());
+            firsts.push(ch.first);
+            lasts.push(ch.last);
+            bytes.extend_from_slice(&ch.data);
+            assert_eq!(ch.pts_ns, 1_234_567, "AU metadata rides every chunk");
+            assert!(ch.keyframe && ch.chunk_aligned && !ch.recovery_anchor);
+        }
+        (bytes, lens, firsts, lasts)
+    }
+
+    /// The invariant PW6 rests on: chunks concatenate to EXACTLY the AU, every cut lands on a
+    /// whole-window boundary (so no window's single `kind` is split across two wire frames), and
+    /// the reassembled stream still walks back to the same codec packets. A cut inside a window
+    /// would hand the client a 4-byte prefix whose body arrives in a different chunk — the
+    /// framing is one-kind-per-window, so there is no way to express that.
+    #[test]
+    fn stream_chunks_tile_the_au_on_window_boundaries() {
+        let bs: Vec<u8> = (0..4000u32).map(|i| (i % 251) as u8).collect();
+        let packets = [(0, 20), (20, 300), (320, 55), (375, 900), (1275, 40)];
+        let chunk = 64;
+        let au = build_au(&packets, &bs, Some(chunk));
+        assert!(au.len() / chunk > 4, "need several windows to cut between");
+        let step = chunk_step(chunk, 3 * chunk);
+        assert_eq!(step, 3 * chunk);
+        let (bytes, lens, firsts, lasts) = drain(AuChunker::new(frame(au.clone()), step));
+        assert_eq!(bytes, au, "chunks concatenate to exactly the AU");
+        assert!(
+            lens.iter().all(|l| l % chunk == 0),
+            "every chunk is a whole number of windows: {lens:?}"
+        );
+        assert!(
+            lens[..lens.len() - 1].iter().all(|&l| l == step),
+            "only the tail chunk may be short: {lens:?}"
+        );
+        assert_eq!(
+            firsts,
+            (0..lens.len()).map(|i| i == 0).collect::<Vec<_>>(),
+            "exactly one opening chunk"
+        );
+        assert_eq!(
+            lasts,
+            (0..lens.len())
+                .map(|i| i + 1 == lens.len())
+                .collect::<Vec<_>>(),
+            "exactly one closing chunk"
+        );
+        // And the client's parse is unchanged by the cutting.
+        let mut expect = Vec::new();
+        for &(o, s) in &packets {
+            expect.extend_from_slice(&bs[o..o + s]);
+        }
+        assert_eq!(walk(&bytes, chunk), expect);
+    }
+
+    /// The step always rounds DOWN to whole windows and never to zero — a target below one window
+    /// degenerates to one window per chunk rather than an empty chunk (which would spin forever).
+    #[test]
+    fn chunk_step_rounds_down_to_whole_windows() {
+        // 262144 / 1408 = 186.2 → 186 whole windows (261 888 B), never the 262 144 asked for.
+        assert_eq!(chunk_step(1408, 256 * 1024), 186 * 1408);
+        assert_eq!(chunk_step(1408, 1408), 1408);
+        assert_eq!(chunk_step(1408, 1407), 1408); // below one window → one window
+        assert_eq!(chunk_step(1408, 0), 1408);
+        assert_eq!(chunk_step(0, 4096), 4096); // defensive: never divides by zero
+    }
+
+    /// An AU that fits one chunk is a single `first && last` piece — the shape the host's
+    /// `handle_chunk` turns into begin+finish on one message, and byte-identical on the wire to
+    /// what the whole-AU path would have sealed.
+    #[test]
+    fn single_chunk_au_opens_and_closes_itself() {
+        let au = vec![7u8; 512];
+        let (bytes, lens, firsts, lasts) = drain(AuChunker::new(frame(au.clone()), 4096));
+        assert_eq!(bytes, au);
+        assert_eq!(lens, vec![512]);
+        assert_eq!(firsts, vec![true]);
+        assert_eq!(lasts, vec![true]);
+    }
+
+    /// The degenerate empty AU still owes exactly ONE self-closing chunk: a chunked poll that
+    /// returned nothing would leave the host's `StreamedAu` open forever (its `begin` fires on
+    /// `first`, its `finish` on `last`).
+    #[test]
+    fn empty_au_still_emits_one_self_closing_chunk() {
+        let mut c = AuChunker::new(frame(Vec::new()), 4096);
+        let ch = c.next().expect("one chunk");
+        assert!(ch.first && ch.last && ch.data.is_empty());
+        assert!(c.next().is_none(), "and never a second one");
+    }
+
+    /// Dense (non-windowed) AUs never stream: there is no window framing to cut on, so a chunk
+    /// boundary would be neither shard-aligned nor a parse boundary.
+    #[test]
+    fn dense_mode_never_streams() {
+        assert!(stream_chunk_step(None).is_none());
+        assert!(stream_chunk_step(Some(0)).is_none());
+    }
 }

crates/pf-encode/src/enc/windows/pyrowave.rs

@@ -128,6 +128,11 @@ pub struct PyroWaveEncoder {
     wire_budget: pyrowave_wire::WireBudget,
     bitstream: Vec<u8>,
     pending: VecDeque<EncodedFrame>,
+    /// The AU currently being handed out in streamed chunks (PW6 — `Some` strictly between a
+    /// `first` chunk and its `last`). See [`pyrowave_wire::AuChunker`]: this backend's encode is
+    /// synchronous, so the AU is COMPLETE before the first chunk leaves — the split is for the
+    /// send side, never an encode/send overlap.
+    chunker: Option<pyrowave_wire::AuChunker>,
 }
 
 // SAFETY: used only from the single encode thread; the pyrowave handles are owned and only touched
@@ -255,6 +260,7 @@ impl PyroWaveEncoder {
                 wire_budget: pyrowave_wire::WireBudget::new(),
                 bitstream: Vec::new(),
                 pending: VecDeque::new(),
+                chunker: None,
             })
         }
     }
@@ -676,10 +682,55 @@ impl Encoder for PyroWaveEncoder {
     }
 
     fn poll(&mut self) -> Result<Option<EncodedFrame>> {
+        // Trait contract: each AU is drained through ONE method. Erroring beats double-emitting
+        // the bytes the chunk cursor already handed out (which would reach the wire twice, under
+        // the same frame index, and fail the receiver's retro-validation).
+        if self.chunker.is_some() {
+            bail!("pyrowave: poll() on an AU already being drained through poll_chunk");
+        }
         Ok(self.pending.pop_front())
     }
 
+    // --- streamed AU (PW6) — see `pyrowave_wire::AuChunker` for what this does and does NOT buy.
+    // Byte-identical to the Linux twin BY CONSTRUCTION: all of the cutting lives in the shared
+    // helper, which compiles and unit-tests on every platform. This file cannot be compiled from
+    // a Linux/macOS dev box, so anything written here directly would ship unverified.
+    fn supports_chunked_poll(&self) -> bool {
+        pyrowave_wire::stream_chunk_step(self.wire_chunk).is_some()
+    }
+
+    fn poll_chunk(&mut self) -> Result<Option<crate::AuChunk>> {
+        // Finish the AU already in flight before opening the next one — the host's `handle_chunk`
+        // keys begin/finish off `first`/`last` and cannot interleave two AUs.
+        if let Some(c) = self.chunker.as_mut() {
+            if let Some(chunk) = c.next() {
+                return Ok(Some(chunk));
+            }
+            self.chunker = None;
+        }
+        let Some(f) = self.pending.pop_front() else {
+            return Ok(None);
+        };
+        // No blocking wait here (the trait allows one): `submit` already ran the whole encode
+        // synchronously, so an AU in `pending` is complete by construction.
+        match pyrowave_wire::stream_chunk_step(self.wire_chunk) {
+            Some(step) => Ok(self
+                .chunker
+                .insert(pyrowave_wire::AuChunker::new(f, step))
+                .next()),
+            // Unarmed / dense: the trait's own default shape, so a host that polls chunks anyway
+            // still gets whole AUs.
+            None => Ok(Some(crate::AuChunk::whole(f))),
+        }
+    }
+
     fn reset(&mut self) -> bool {
+        // A rebuild forfeits every in-flight frame — including an AU only half-handed-out through
+        // `poll_chunk`. Dropping the cursor here (ahead of every `pending.clear()` arm below) is
+        // what keeps the next `poll_chunk` from splicing the tail of a dead AU onto a fresh one;
+        // the host sees a `first` without the previous `last`, logs "streamed AU abandoned
+        // mid-flight" and lets the client age that frame out.
+        self.chunker = None;
         // Cheap in-place rebuild: recreate only the pyrowave encoder object (no rate-control /
         // reference state to preserve). The device, imported textures and fence survive.
         // SAFETY: encode is synchronous (no work in flight); the device outlives the swapped encoder.

crates/pf-host-config/src/lib.rs

@@ -260,6 +260,18 @@ pub struct HostConfig {
     /// encode, so this is the knob that decides how bright "white" looks on the client's panel.
     /// `None` = leave gamescope's own default.
     pub gamescope_sdr_nits: Option<u32>,
+    /// `PUNKTFUNK_GAMESCOPE_REFRESH_RATES` — extra refresh rates (Hz, comma-separated) a gamescope
+    /// session offers its clients on top of the one it runs at, e.g. `60,90,120`.
+    ///
+    /// A headless gamescope has no EDID, so it cannot work out what else its display could run at:
+    /// on a stock build it advertises exactly ONE rate and Steam's in-session display settings show
+    /// a single entry. Our `+pfhdr3` build takes this list (`--custom-refresh-rates`) and publishes
+    /// it, which is what puts real choices in that menu. The session's own rate is always included
+    /// whatever is set here, so this can only ever ADD options.
+    ///
+    /// Empty (the default) = advertise only the negotiated rate. Ignored on a stock gamescope,
+    /// which has no flag to take it.
+    pub gamescope_refresh_rates: Vec<u32>,
     /// `PUNKTFUNK_RECOVER_SESSION_CMD` — operator hook fired (debounced) when a client connects while NO
     /// graphical session is live for this uid: the state a compositor crash leaves behind (gnome-shell
     /// SIGSEGV → GDM greeter, whose auto-login is once-per-boot, so the box would otherwise need a walk-up
@@ -379,6 +391,12 @@ impl HostConfig {
             gamescope_sdr_nits: val("PUNKTFUNK_GAMESCOPE_SDR_NITS")
                 .and_then(|s| s.trim().parse::<u32>().ok())
                 .filter(|n| (1..=10_000).contains(n)),
+            // Unparseable entries are DROPPED rather than failing the host: this only ever widens a
+            // menu, and the session's own rate is added back unconditionally, so the worst a typo
+            // can cost is the extra option the operator wanted — never the session.
+            gamescope_refresh_rates: parse_refresh_rates(
+                val("PUNKTFUNK_GAMESCOPE_REFRESH_RATES").as_deref(),
+            ),
             recover_session_cmd: val("PUNKTFUNK_RECOVER_SESSION_CMD")
                 .filter(|s| !s.trim().is_empty()),
             on_connect_cmd: val("PUNKTFUNK_ON_CONNECT_CMD").filter(|s| !s.trim().is_empty()),
@@ -397,6 +415,20 @@ impl HostConfig {
     }
 }
 
+/// `"60, 90,120"` → `[60, 90, 120]`, sorted and deduped. Junk entries and out-of-range rates are
+/// skipped rather than rejected wholesale — see the call site for why. Pure + unit-tested.
+fn parse_refresh_rates(raw: Option<&str>) -> Vec<u32> {
+    let mut out: Vec<u32> = raw
+        .unwrap_or_default()
+        .split(',')
+        .filter_map(|s| s.trim().parse::<u32>().ok())
+        .filter(|&hz| (1..=1000).contains(&hz))
+        .collect();
+    out.sort_unstable();
+    out.dedup();
+    out
+}
+
 impl HostConfig {
     /// The rate to hand the compositor as the GAME's refresh: the session's rate, capped by
     /// [`Self::max_fps`]. Only the compositor's game-facing rate goes through here — the session's
@@ -446,6 +478,24 @@ mod tests {
         assert_eq!(c.game_fps(0), 0);
     }
 
+    #[test]
+    fn refresh_rate_list_parses_and_tolerates_junk() {
+        assert_eq!(parse_refresh_rates(Some("60,90,120")), vec![60, 90, 120]);
+        // Spaces, unsorted input and duplicates all normalise.
+        assert_eq!(
+            parse_refresh_rates(Some(" 120, 60 ,90, 60")),
+            vec![60, 90, 120]
+        );
+        // Unset and empty are the default: advertise only the session's own rate.
+        assert!(parse_refresh_rates(None).is_empty());
+        assert!(parse_refresh_rates(Some("")).is_empty());
+        assert!(parse_refresh_rates(Some("   ")).is_empty());
+        // A typo costs its own entry, never the whole list — the knob only widens a menu.
+        assert_eq!(parse_refresh_rates(Some("60,abc,120")), vec![60, 120]);
+        // Out of range in both directions (0 is not a refresh rate; 1920 is a width).
+        assert_eq!(parse_refresh_rates(Some("0,60,1920")), vec![60]);
+    }
+
     #[test]
     fn audio_output_mode_parses_its_spellings() {
         for (s, want) in [

crates/pf-presenter/src/run.rs

@@ -550,7 +550,15 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
             Some((x, y)) => b.position(x, y),
             None => b.position_centered(),
         };
-        b.resizable().vulkan();
+        // HIGH_PIXEL_DENSITY: give us a backbuffer in the panel's REAL pixels. Without it
+        // SDL leaves the Wayland surface at buffer scale 1, so on a fractionally scaled
+        // output (KDE at 150 %: a 2560×1600 panel reported as 1707×1067 points) the
+        // swapchain is built at 1707×1067 and the compositor upscales it to the glass —
+        // a 2560×1600 stream is resampled DOWN and back UP, and looks it. The flag only
+        // widens `size_in_pixels()`; `size()` stays logical, which is what the persisted
+        // window size and SDL's own mouse coordinates are in, and both callers already
+        // use the right one.
+        b.resizable().vulkan().high_pixel_density();
         if opts.fullscreen {
             b.fullscreen();
         }
@@ -638,17 +646,29 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
         // translation automatically — the GTK launcher never turned it off either).
         gamepad.set_menu_mode(true);
     }
+    // Gaming Mode's Steam menu / QAM drive the SAME physical pad we forward, and gamescope
+    // never takes our X focus away (it resolves focus per Xwayland ctx, and we are alone in
+    // ours), so SDL's own background-input gate cannot fire there. `None` everywhere else,
+    // where window focus IS the signal — see the FocusLost/FocusGained arms below.
+    #[cfg(target_os = "linux")]
+    let overlay_focus = pf_client_core::overlay_focus::OverlayFocus::start();
+    // Two independent reasons the pad is not ours — window focus and the gamescope overlay —
+    // OR'd into ONE value that is pushed to the service on an edge. Kept as separate inputs
+    // rather than one flag each source writes: either would otherwise clear the other's mask
+    // (a focus-loss mask undone by the next overlay poll saying "no overlay", and vice versa).
+    let mut focus_lost = false;
+    let mut mask_applied = false;
 
     // The native display mode — the `0 = native` fallback for the requested stream mode
     // (the GTK client reads the monitor under its window; same idea).
     let native = window
         .get_display()
         .and_then(|d| d.get_mode())
-        .map(|m| Mode {
-            width: m.w.max(0) as u32,
-            height: m.h.max(0) as u32,
-            refresh_hz: m.refresh_rate.round().max(0.0) as u32,
-        })
+        .map(|m| native_mode(m.w, m.h, m.pixel_density, m.refresh_rate))
+        .ok()
+        // A zero-sized mode is as useless as no mode at all — only `Err` used to reach
+        // the fallback, so a display that reported 0×0 streamed a 0×0 request.
+        .filter(|m: &Mode| m.width > 0 && m.height > 0)
         .unwrap_or(Mode {
             width: 1920,
             height: 1080,
@@ -750,8 +770,17 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                                 tracing::info!("focus lost — input released");
                             }
                         }
+                        // Controllers go with the keyboard and mouse. SDL already stops
+                        // delivering their PRESSES here, but nothing zeroed what the host
+                        // still believes is held — so a stick deflected at the moment focus
+                        // went away kept steering. Masking flushes it neutral.
+                        focus_lost = true;
                     }
                     WindowEvent::FocusGained => {
+                        // Unlike capture, the controller mask has no "the user meant it"
+                        // variant to respect — it exists only to mirror who owns the pad —
+                        // so regaining focus always lifts its half.
+                        focus_lost = false;
                         // An auto-release (Alt-Tab) undoes itself; a chord release
                         // stays released until the user opts back in.
                         if let Some(cap) = stream.as_mut().and_then(|s| s.capture.as_mut()) {
@@ -1062,6 +1091,18 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                 other => pump.handle_event(other),
             }
         }
+        // Who owns the pad right now: window focus, plus Gaming Mode's overlay signal where it
+        // exists (one relaxed atomic load; `None` off gamescope). Edge-triggered — the service
+        // hears only about CHANGES, so an open QAM doesn't re-flush the pads every iteration.
+        #[cfg(target_os = "linux")]
+        let overlay_now = overlay_focus.as_ref().is_some_and(|of| of.is_open());
+        #[cfg(not(target_os = "linux"))]
+        let overlay_now = false;
+        let want_mask = focus_lost || overlay_now;
+        if want_mask != mask_applied {
+            mask_applied = want_mask;
+            gamepad.set_masked(want_mask);
+        }
         pump.tick();
         // One coalesced MouseMove per iteration — pure motion must reach the host
         // without waiting for a click/key to flush it.
@@ -2136,6 +2177,37 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
     Ok(outcome)
 }
 
+/// An `SDL_DisplayMode` as the panel's REAL pixels — the `0 = native` stream mode.
+///
+/// SDL3 reports a display mode in SCREEN COORDINATES, not pixels, and hands you the ratio
+/// between the two separately as `pixel_density`. On X11 and Windows that ratio is always
+/// 1.0 (SDL never sets it there, and `SDL_video.c` normalizes the unset 0.0 up to 1.0), so
+/// this is a no-op — but under a Wayland compositor doing FRACTIONAL scaling it is the
+/// whole ballgame: KDE at 150 % advertises a 2560×1600 panel as 1707×1067 points with
+/// `pixel_density` ≈ 1.4997, and taking `m.w`/`m.h` raw is what made "Native resolution"
+/// negotiate 1706×1066 (1707×1067 even-floored by `render_scale::apply`) and stream a
+/// blurry two-thirds-size image. `SDL_VIDEO_WAYLAND_SCALE_TO_DISPLAY=1` is the same fix
+/// from the outside — it makes SDL report the native mode itself — which is why setting it
+/// was a workaround.
+///
+/// The density is the exact `pixels / points` ratio SDL derived from the output, so the
+/// multiplication recovers the panel size to the pixel rather than approximating it.
+fn native_mode(w: i32, h: i32, pixel_density: f32, refresh_rate: f32) -> Mode {
+    // A non-finite or non-positive density is SDL telling us nothing useful; 1× at least
+    // preserves the pre-fix behaviour instead of collapsing the mode to zero.
+    let density = if pixel_density.is_finite() && pixel_density > 0.0 {
+        pixel_density
+    } else {
+        1.0
+    };
+    let px = |v: i32| (v.max(0) as f32 * density).round().max(0.0) as u32;
+    Mode {
+        width: px(w),
+        height: px(h),
+        refresh_hz: refresh_rate.round().max(0.0) as u32,
+    }
+}
+
 /// Match-window (D1): replace the params' requested w/h with the window's physical pixel
 /// size — even-floored (the host's `validate_dimensions` rejects odd) and clamped to a
 /// sane minimum — keeping the resolved refresh. Under `--fullscreen` the window IS the
@@ -2908,6 +2980,52 @@ fn stats_text(
 mod tests {
     use super::*;
 
+    /// The field report this exists for: CachyOS/KDE Plasma 6.7.4 Wayland, a 2560×1600@165
+    /// laptop panel at 150 % scaling. KDE advertises the output as 1707×1067 points, SDL
+    /// hands that back as the desktop mode with `pixel_density` = 2560/1707, and "Native
+    /// resolution" streamed 1706×1066 — the points, even-floored by `render_scale::apply`.
+    #[test]
+    fn native_is_the_panels_pixels_under_fractional_wayland_scaling() {
+        // SDL derives the density as the exact pixels-per-point ratio of the output.
+        let density = 2560.0 / 1707.0;
+        let m = native_mode(1707, 1067, density, 165.0);
+        assert_eq!((m.width, m.height, m.refresh_hz), (2560, 1600, 165));
+        // …and it survives the even-floor the host's `validate_dimensions` forces, which is
+        // where 1707×1067 lost its odd pixel and became the reported 1706×1066.
+        assert_eq!(
+            punktfunk_core::render_scale::apply(m.width, m.height, 1.0, 8192),
+            (2560, 1600)
+        );
+        assert_eq!(
+            punktfunk_core::render_scale::apply(1707, 1067, 1.0, 8192),
+            (1706, 1066),
+            "the pre-fix mode, kept here so the regression is legible"
+        );
+    }
+
+    #[test]
+    fn native_is_unchanged_where_the_density_is_one() {
+        // X11, Windows, and Wayland at 100 % all report 1.0 — the fix must be inert there.
+        let m = native_mode(2560, 1600, 1.0, 165.0);
+        assert_eq!((m.width, m.height, m.refresh_hz), (2560, 1600, 165));
+        // Integer scaling (a 200 % 4K panel reported as 1920×1080 points) doubles cleanly.
+        let m = native_mode(1920, 1080, 2.0, 60.0);
+        assert_eq!((m.width, m.height), (3840, 2160));
+    }
+
+    #[test]
+    fn a_nonsense_density_falls_back_to_one_rather_than_zeroing_the_mode() {
+        // SDL normalizes an unset density to 1.0, but this must not be the one place a
+        // driver quirk can hand the host a 0×0 mode request.
+        for bogus in [0.0, -1.0, f32::NAN, f32::INFINITY] {
+            let m = native_mode(2560, 1600, bogus, 60.0);
+            assert_eq!((m.width, m.height), (2560, 1600), "density {bogus}");
+        }
+        // A negative mode size is clamped, not wrapped into a huge u32.
+        let m = native_mode(-1, -1, 1.5, 60.0);
+        assert_eq!((m.width, m.height), (0, 0));
+    }
+
     #[test]
     fn overlay_scale_follows_dpi_and_survives_a_bogus_display() {
         // 100 % / 96 dpi is the identity — the chrome keeps the size it always had.

crates/pf-vdisplay/src/lib.rs

@@ -130,6 +130,22 @@ impl Compositor {
         }
     }
 
+    /// Does this backend need a compositor that is ALREADY RUNNING for this uid?
+    ///
+    /// Every desktop backend attaches to a live session — it asks Mutter/KWin/sway/Hyprland to mint
+    /// a virtual output over their IPC, so with nothing running there is no one to ask and `create`
+    /// can only fail (on GNOME: `RemoteDesktop.CreateSession:
+    /// org.freedesktop.DBus.Error.ServiceUnknown`). [`Compositor::Gamescope`] is the exception: it
+    /// stands its own session up from nothing (bare headless spawn / managed takeover), which is
+    /// exactly why a headless box pins to it.
+    ///
+    /// Callers use this to tell "the session is up" from "the session is a corpse" BEFORE marching a
+    /// client into a doomed bring-up — the state a compositor crash leaves behind (gnome-shell
+    /// SIGSEGV → GDM greeter, whose auto-login is once-per-boot, so it never returns on its own).
+    pub fn needs_live_session(self) -> bool {
+        !matches!(self, Compositor::Gamescope)
+    }
+
     /// Human label for UIs.
     pub fn label(self) -> &'static str {
         match self {

crates/pf-vdisplay/src/vdisplay/linux/gamescope.rs

@@ -27,6 +27,7 @@ mod heads;
 mod splash;
 use discovery::{
     check_gamescope_version, find_gamescope_eis_socket, find_gamescope_node, gamescope_bin,
+    gamescope_can_composite_external_overlay, gamescope_can_offer_refresh_rates,
     gamescope_node_present, poll_managed_node, wait_for_node,
 };
 pub(crate) use discovery::{
@@ -1153,17 +1154,9 @@ fn gamescope_argvs() -> Vec<Vec<String>> {
 /// also the final filter that separates a compositor from anything else [`gamescope_argvs`] let by.
 fn current_gamescope_output_size() -> Option<(u32, u32)> {
     gamescope_argvs().into_iter().find_map(|args| {
-        let flag = |names: &[&str]| -> Option<u32> {
-            args.iter().enumerate().find_map(|(i, a)| {
-                names
-                    .contains(&a.as_str())
-                    .then(|| args.get(i + 1).and_then(|v| v.parse().ok()))
-                    .flatten()
-            })
-        };
         match (
-            flag(&["-W", "--output-width"]),
-            flag(&["-H", "--output-height"]),
+            argv_u32(&args, &["-W", "--output-width"]),
+            argv_u32(&args, &["-H", "--output-height"]),
         ) {
             (Some(w), Some(h)) => Some((w, h)),
             _ => None,
@@ -1171,6 +1164,104 @@ fn current_gamescope_output_size() -> Option<(u32, u32)> {
     })
 }
 
+/// The numeric value following the first of `names` present in `argv`. Pure + unit-tested — it is
+/// the shared reader behind both the output-size probe above and the mode verification below.
+fn argv_u32(argv: &[String], names: &[&str]) -> Option<u32> {
+    argv.iter().enumerate().find_map(|(i, a)| {
+        names
+            .contains(&a.as_str())
+            .then(|| argv.get(i + 1).and_then(|v| v.parse().ok()))
+            .flatten()
+    })
+}
+
+/// Did the MODE we asked an indirectly-spawned session for actually reach its gamescope?
+///
+/// [`verify_managed_spawn_flags`] answers the same question for the capability flags and REFUSES
+/// the session when they are missing, because the retry then resolves a different (correct) plan.
+/// The mode has no such recovery: relaunching would hand the session the exact same environment and
+/// lose it the same way, so refusing would only loop. It is not silent either, though — and it used
+/// to be, in the way that costs the most:
+///
+/// `--nested-refresh` is the ONLY refresh a headless gamescope has. `CHeadlessBackend::Init`
+/// assigns `g_nOutputRefresh = g_nNestedRefresh`, defaulting to **60 Hz** when the flag is absent,
+/// and that one number is what the session composites at, what `vblankmanager` paces to, and what
+/// Steam and every game are told the display runs at. It reaches a `gamescope-session-plus` only
+/// through the `GAMESCOPE_BIN` wrapper — which the session script is free to lose (a `sessions.d`
+/// file sourced with `set -a` can reassign `GAMESCOPE_BIN`; one that sets `GAMESCOPECMD` outright
+/// skips the whole builder). When that happened the stream still ran, still looked right, and still
+/// showed the client's own fps counter at the negotiated rate — because the encode loop repeats the
+/// held frame — while the game underneath was capped to 60. Field report 2026-08-08.
+///
+/// So: warn, name the numbers, and carry on. Same "any running gamescope carrying it" rule as the
+/// flag check, and the same silence when `/proc` cannot be read.
+fn warn_if_mode_lost(mode: Mode, want_hz: u32) {
+    let argvs = gamescope_argvs();
+    let lost = mode_mismatch(mode.width, mode.height, want_hz, &argvs);
+    if lost.is_empty() {
+        return;
+    }
+    tracing::warn!(
+        lost = %lost.join(", "),
+        "gamescope: the session did not start at the mode we asked for — the session script \
+         dropped GAMESCOPE_BIN / SCREEN_WIDTH / SCREEN_HEIGHT. A headless gamescope reports \
+         `--nested-refresh` as its ONE refresh rate (60 Hz when the flag never arrives), so games \
+         and Steam will believe the display runs at that rate however fast the stream is. Install \
+         punktfunk-gamescope, or check /etc/gamescope-session-plus/sessions.d/ for a file that \
+         overrides GAMESCOPE_BIN or sets GAMESCOPECMD"
+    );
+}
+
+/// Which parts of the requested mode no running gamescope was started with, as human-readable
+/// `asked=…, got=…` fragments. Empty when it matches — or when there is nothing to compare against,
+/// which is the same fail-open rule [`missing_flags`] has and for the same reason. Pure +
+/// unit-tested.
+fn mode_mismatch(want_w: u32, want_h: u32, want_hz: u32, argvs: &[Vec<String>]) -> Vec<String> {
+    if argvs.is_empty() {
+        return Vec::new();
+    }
+    let mut lost = Vec::new();
+    let sizes: Vec<(u32, u32)> = argvs
+        .iter()
+        .filter_map(|a| {
+            Some((
+                argv_u32(a, &["-W", "--output-width"])?,
+                argv_u32(a, &["-H", "--output-height"])?,
+            ))
+        })
+        .collect();
+    // No gamescope carries an output size at all → we cannot tell ours apart from a nested one;
+    // stay quiet rather than warn on every box that runs a second gamescope.
+    if !sizes.is_empty() && !sizes.contains(&(want_w, want_h)) {
+        lost.push(format!(
+            "resolution asked={want_w}x{want_h}, got={}",
+            sizes
+                .iter()
+                .map(|(w, h)| format!("{w}x{h}"))
+                .collect::<Vec<_>>()
+                .join("/")
+        ));
+    }
+    let rates: Vec<u32> = argvs
+        .iter()
+        .filter_map(|a| argv_u32(a, &["-r", "--nested-refresh"]))
+        .collect();
+    if !rates.contains(&want_hz) {
+        lost.push(match rates.as_slice() {
+            // The flag is absent everywhere — the exact shape that silently yields 60 Hz.
+            [] => format!(
+                "refresh asked={want_hz}Hz, got=no --nested-refresh at all (gamescope defaults to \
+                 60Hz headless)"
+            ),
+            got => format!(
+                "refresh asked={want_hz}Hz, got={}Hz",
+                got.iter().map(u32::to_string).collect::<Vec<_>>().join("/")
+            ),
+        });
+    }
+    lost
+}
+
 /// Did the flags we passed an INDIRECTLY-spawned session actually reach its gamescope?
 ///
 /// The bare spawn builds argv itself and cannot lose them. The two managed modes can: a
@@ -2337,12 +2428,29 @@ fn launch_session(client: &str, unit_name: &str, mode: Mode, hdr: bool) -> Resul
     let wrapper = write_gamescope_bin_wrapper()?;
     stop_session(unit_name); // clear any stale unit + relay so a relaunch is clean
     let hz = mode.refresh_hz.max(1);
-    // The two rates are deliberately different when the frame limiter is set. CUSTOM_REFRESH_RATES
-    // generates the mode the session ADVERTISES, which must stay the client's — that is what makes
-    // games see the real refresh instead of the box's EDID. PF_HZ becomes `--nested-refresh`, the
-    // rate the game is clamped to, and is the only one the limiter touches. Identical when it's
-    // unset, which is the default.
+    // ONE rate reaches gamescope, and it is `--nested-refresh` (via the wrapper's `PF_HZ`). On the
+    // headless backend that flag IS the output refresh — `CHeadlessBackend::Init` assigns
+    // `g_nOutputRefresh = g_nNestedRefresh` — so it is simultaneously the rate the session
+    // composites at, the rate `vblankmanager` paces to, and the rate Steam and every game are told
+    // the display runs at. When the frame limiter (`PUNKTFUNK_MAX_FPS`) is set they all drop
+    // together; that is the trade the knob is, and it is off by default.
+    //
+    // `CUSTOM_REFRESH_RATES` below does NOT do this, whatever its name suggests: it is the *set* of
+    // rates the session may offer, and `gamescope-session-plus` gates it on the binary having
+    // `--custom-refresh-rates`, which no upstream gamescope has ever had. On a stock gamescope it
+    // is inert (it was a silent no-op for years); on our `+pfhdr3` build it is what puts more than
+    // one entry in Steam's refresh menu. Either way it cannot fix a wrong `--nested-refresh`.
     let game = game_hz(mode.refresh_hz);
+    // The advertised SET, which always contains the rate we actually run at.
+    let offered = {
+        let mut r = pf_host_config::config().gamescope_refresh_rates.clone();
+        if !r.contains(&hz) {
+            r.push(hz);
+        }
+        r.sort_unstable();
+        r.dedup();
+        r.iter().map(u32::to_string).collect::<Vec<_>>().join(",")
+    };
     let start_unit = || -> Result<()> {
         let status = Command::new("systemd-run")
             .args(["--user", "--collect", &format!("--unit={unit_name}")])
@@ -2366,7 +2474,7 @@ fn launch_session(client: &str, unit_name: &str, mode: Mode, hdr: bool) -> Resul
             ))
             .arg(format!("--setenv=GAMESCOPE_BIN={}", wrapper.display()))
             .arg("--setenv=DRM_MODE=cvt")
-            .arg(format!("--setenv=CUSTOM_REFRESH_RATES={hz}"))
+            .arg(format!("--setenv=CUSTOM_REFRESH_RATES={offered}"))
             .arg("--")
             .arg(SESSION_PLUS_BIN)
             .arg(client)
@@ -2394,6 +2502,9 @@ fn launch_session(client: &str, unit_name: &str, mode: Mode, hdr: bool) -> Resul
                 stop_session(unit_name);
                 return Err(e);
             }
+            // Loud, but not fatal — see [`warn_if_mode_lost`] for why this one warns where the
+            // capability flags above refuse.
+            warn_if_mode_lost(mode, game);
             return Ok(id);
         }
         if Instant::now() >= deadline {
@@ -2526,7 +2637,15 @@ fn add_bare_gamescope_args(
     if grab_cursor {
         command.arg("--force-grab-cursor");
     }
-    for arg in hdr_args(hdr).into_iter().chain(cursor_args()) {
+    // `-r` above is what this headless session will REPORT as its refresh (the headless backend
+    // assigns `g_nOutputRefresh = g_nNestedRefresh`), so it is already correct here. This adds the
+    // rest of the SET the in-session UI may offer — the bare spawn passes it directly, with none of
+    // the session-script indirection the managed path has to route it through.
+    for arg in hdr_args(hdr)
+        .into_iter()
+        .chain(cursor_args())
+        .chain(refresh_rate_args(hz))
+    {
         command.arg(arg);
     }
     command.args(["--xwayland-count", "1", "--"]);
@@ -2571,11 +2690,48 @@ fn hdr_args(hdr: bool) -> Vec<String> {
 /// host-side (it costs the host a full-frame pass, and on the zero-CSC encode source it cannot be
 /// done at all). Empty on a stock gamescope, which is exactly the old behaviour.
 fn cursor_args() -> Vec<String> {
+    let mut args = Vec::new();
     if gamescope_can_composite_cursor() {
-        vec!["--pipewire-composite-cursor".to_string()]
-    } else {
-        Vec::new()
+        args.push("--pipewire-composite-cursor".to_string());
     }
+    // The external overlay (mangoapp — the Deck UI's fps/frametime readout, patch level 4+). Unlike
+    // the cursor there is no host-side fallback: the host cannot reconstruct another process's
+    // overlay window, so without this the layer is simply absent from every gamescope stream.
+    if gamescope_can_composite_external_overlay() {
+        args.push("--pipewire-composite-external-overlay".to_string());
+    }
+    args
+}
+
+/// `--custom-refresh-rates <list>` when the resolved gamescope has it (patch level 3+): the rates a
+/// HEADLESS session may offer its clients.
+///
+/// Without it a headless connector advertises exactly one rate, so Steam's in-session display
+/// settings show a single entry and a game reads the display as that one number. `session_hz` is
+/// always in the list — it is the mode the session actually runs at, and an advertised set that
+/// excluded it would be a lie in the other direction.
+///
+/// The operator can widen the set (`PUNKTFUNK_GAMESCOPE_REFRESH_RATES=60,90,120`) so the in-session
+/// UI offers real choices; unset, we advertise the one rate we run at, which is what the client
+/// asked for.
+fn refresh_rate_args(session_hz: u32) -> Vec<String> {
+    if !gamescope_can_offer_refresh_rates() {
+        return Vec::new();
+    }
+    let mut rates = pf_host_config::config().gamescope_refresh_rates.clone();
+    if !rates.contains(&session_hz) {
+        rates.push(session_hz);
+    }
+    rates.sort_unstable();
+    rates.dedup();
+    vec![
+        "--custom-refresh-rates".to_string(),
+        rates
+            .iter()
+            .map(u32::to_string)
+            .collect::<Vec<_>>()
+            .join(","),
+    ]
 }
 
 /// Spawn `gamescope --backend headless -W w -H h -r hz -- <app>`. The app comes from
@@ -2717,7 +2873,7 @@ mod tests {
     use super::{
         cgroup_is_punktfunk_owned, cgroup_under_user_manager, connected_connector_under,
         display_manager_unit_under, dm_plan, dm_survives_masked_unit, game_hz, hdr_args,
-        is_steam_launch, missing_flags, nested_wrapper_script, sentinel_advanced,
+        is_steam_launch, missing_flags, mode_mismatch, nested_wrapper_script, sentinel_advanced,
         shape_dedicated_command,
     };
 
@@ -2949,6 +3105,63 @@ mod tests {
         assert!(!cgroup_is_punktfunk_owned(""));
     }
 
+    /// The silent-60Hz guard. A headless gamescope reports `--nested-refresh` as its ONE refresh
+    /// rate and falls back to 60 Hz when the flag never arrives, so a session that lost the
+    /// `GAMESCOPE_BIN` wrapper streams at the client's rate while telling every game it is 60 —
+    /// the exact shape of the 2026-08-08 field report, and invisible without this.
+    #[test]
+    fn mode_mismatch_names_what_the_session_actually_got() {
+        let argv = |s: &str| -> Vec<String> { s.split(' ').map(str::to_string).collect() };
+
+        // The good case: our own managed spawn, carrying everything we asked for.
+        let ok = vec![argv(
+            "/usr/bin/gamescope --backend headless -W 1920 -H 1080 --nested-refresh 120 --steam",
+        )];
+        assert!(mode_mismatch(1920, 1080, 120, &ok).is_empty());
+
+        // THE field case: the wrapper was dropped, so there is no `--nested-refresh` anywhere and
+        // gamescope silently ran its 60 Hz default. Size still landed (SCREEN_WIDTH survived).
+        let lost = vec![argv(
+            "/usr/bin/gamescope --backend headless -W 1920 -H 1080 --steam",
+        )];
+        let got = mode_mismatch(1920, 1080, 120, &lost);
+        assert_eq!(got.len(), 1, "only the refresh is wrong: {got:?}");
+        assert!(got[0].contains("asked=120Hz"), "{got:?}");
+        assert!(got[0].contains("no --nested-refresh at all"), "{got:?}");
+
+        // A wrong rate is reported with the number it actually got, not just "missing".
+        let wrong = vec![argv("gamescope -W 1920 -H 1080 --nested-refresh 60")];
+        let got = mode_mismatch(1920, 1080, 120, &wrong);
+        assert_eq!(got.len(), 1);
+        assert!(got[0].contains("got=60Hz"), "{got:?}");
+
+        // Resolution lost too (SCREEN_WIDTH/HEIGHT dropped as well) — both are named.
+        let both = vec![argv("gamescope -W 1280 -H 720")];
+        assert_eq!(mode_mismatch(1920, 1080, 120, &both).len(), 2);
+
+        // Fail OPEN, exactly like `missing_flags`: nothing to compare against says nothing. A box
+        // with a second gamescope that carries no output size must not produce a false alarm.
+        assert!(mode_mismatch(1920, 1080, 120, &[]).is_empty());
+
+        // ANY running gamescope carrying the mode satisfies it — a Deck commonly runs a nested one
+        // beside the session, and demanding that every gamescope match would reject a good session.
+        let two = vec![
+            argv("gamescope -W 1280 -H 800 --nested-refresh 60"),
+            argv("gamescope -W 1920 -H 1080 --nested-refresh 120"),
+        ];
+        assert!(mode_mismatch(1920, 1080, 120, &two).is_empty());
+
+        // The long spellings are read too.
+        let long = vec![argv(
+            "gamescope --output-width 1920 --output-height 1080 --nested-refresh 120",
+        )];
+        assert!(mode_mismatch(1920, 1080, 120, &long).is_empty());
+
+        // A flag with no value after it must not panic or read past the end.
+        let truncated = vec![argv("gamescope -W 1920 -H 1080 --nested-refresh")];
+        assert_eq!(mode_mismatch(1920, 1080, 120, &truncated).len(), 1);
+    }
+
     /// The silent-cursor guard: a managed session that ignored `GAMESCOPE_BIN` / the PATH shim runs
     /// a stock gamescope, and the host — already told the compositor would paint the pointer —
     /// paints none either. Only a compositor we can SEE, missing a flag we can NAME, may fail.

crates/pf-vdisplay/src/vdisplay/linux/gamescope/discovery.rs

@@ -449,6 +449,34 @@ pub(crate) fn gamescope_can_composite_cursor() -> bool {
     gamescope_patch_level() >= 2 && !flags_lost()
 }
 
+/// Does the resolved gamescope let us hand a headless session the list of refresh rates it may
+/// offer (`--custom-refresh-rates`)?
+///
+/// Below this level a headless gamescope advertises **one** rate — whatever `--nested-refresh`
+/// resolved to, or its own 60 Hz default — and no resolution list at all, because its connector
+/// returns empty spans from `GetModes()`/`GetValidDynamicRefreshRates()` and reports an INTERNAL
+/// screen (which makes `update_mode_atoms` delete the mode-list atom outright). So on a stock
+/// gamescope, Steam's in-session display settings show exactly one refresh rate and no
+/// resolutions, and games read the display as 60 Hz whatever the client negotiated.
+///
+/// `gamescope-session-plus` has probed for this flag for years (`CUSTOM_REFRESH_RATES` is gated on
+/// `gamescope --help` mentioning it) — upstream simply never had it, so the env var it plumbs was
+/// a no-op everywhere.
+pub(crate) fn gamescope_can_offer_refresh_rates() -> bool {
+    gamescope_patch_level() >= 3 && !flags_lost()
+}
+
+/// Can the resolved gamescope paint the EXTERNAL OVERLAY — mangoapp, the Deck-UI fps/frametime
+/// readout — into its PipeWire node (`--pipewire-composite-external-overlay`)?
+///
+/// `paint_pipewire` has never referenced that layer on any upstream version, so a client whose
+/// only view of the session is the node sees the overlay it just enabled simply not appear.
+/// Unlike the cursor there is no host-side substitute: the host cannot reconstruct someone else's
+/// overlay window.
+pub(crate) fn gamescope_can_composite_external_overlay() -> bool {
+    gamescope_patch_level() >= 4 && !flags_lost()
+}
+
 /// Has a spawn been observed where our flags did NOT reach the gamescope process?
 ///
 /// The binary probe above answers "can it", which is all the bare spawn needs — there we build

crates/pf-vdisplay/src/vdisplay/linux/kwin.rs

@@ -13,8 +13,11 @@
 //! So an interactive Plasma session does NOT hand it to a bare client — the host packages ship
 //! `io.unom.Punktfunk.Host.desktop` (`Exec=/usr/bin/punktfunk-host`,
 //! `X-KDE-Wayland-Interfaces=zkde_screencast_unstable_v1,…`) so it is present before the host first
-//! connects. The headless test path instead exposes it to bare clients via
-//! `KWIN_WAYLAND_NO_PERMISSION_CHECKS=1`. The compositor backend must implement
+//! connects. That identification is also why **the host binary must carry no file capability**: a
+//! process holding capabilities KWin lacks is one the kernel will not let KWin resolve
+//! `/proc/<pid>/exe` for, so it can never be matched to a `.desktop` no matter how correctly the
+//! file is installed (see [`capability_denial_hint`]). The headless test path instead exposes it to
+//! bare clients via `KWIN_WAYLAND_NO_PERMISSION_CHECKS=1`. The compositor backend must implement
 //! `createVirtualOutput`: the **DRM backend** (any version) or the **VirtualBackend since KWin
 //! 6.5.6** (`kwin_wayland --virtual`); on `--virtual` < 6.5.6 the request fails with
 //! "Could not find output". We talk raw Wayland on `$WAYLAND_DISPLAY`, so the host must run inside
@@ -1071,6 +1074,74 @@ impl Drop for StopOnDrop {
     }
 }
 
+/// Extra sentence appended to every "KWin never advertised the screencast global" error when this
+/// process carries capabilities — the one cause that is completely invisible from the Wayland side.
+///
+/// KWin authorizes a restricted interface by resolving the *client's* `/proc/<pid>/exe` and
+/// matching it against an installed `.desktop`. The kernel refuses that readlink to any reader
+/// whose effective set is not a superset of the target's **permitted** set
+/// (`cap_ptrace_access_check`), and KWin has no capabilities at all. So a host binary carrying any
+/// file capability is simply unidentifiable: `executablePath()` comes back empty, no `.desktop` can
+/// match, and the global is never advertised — indistinguishable, from here, from a missing
+/// `.desktop`. Neither half of the obvious workaround helps: `prctl(PR_SET_DUMPABLE, 1)` leaves the
+/// permitted-set check failing, and moving the grant to systemd `AmbientCapabilities=` lands the
+/// capability in the same permitted set. Only an uncapped binary is identifiable.
+///
+/// This is not hypothetical: 0.26.0-1 setcap'd `cap_sys_nice` on the host for the GPU-priority
+/// lever and took out desktop streaming on every KDE box until the capability was removed again.
+fn capability_denial_hint() -> String {
+    let permitted = std::fs::read_to_string("/proc/self/status")
+        .ok()
+        .and_then(|status| permitted_caps_from_status(&status));
+    match permitted {
+        Some(caps) if caps != 0 => format!(
+            " — NOTE: this process carries capabilities (CapPrm={caps:#018x}), which is enough on \
+             its own to cause this: the kernel then refuses KWin the /proc/<pid>/exe read it \
+             identifies clients by, so no .desktop can match however correctly it is installed. \
+             Clear them with `sudo setcap -r /usr/bin/punktfunk-host` and restart the host"
+        ),
+        _ => String::new(),
+    }
+}
+
+/// The permitted-capability mask out of a `/proc/<pid>/status` body, or `None` if the field is
+/// absent/unparseable. The kernel prints it as a tab-separated 16-digit hex word with no `0x`
+/// (`CapPrm:\t0000000000800000` = CAP_SYS_NICE), which is what the split-and-radix-16 parse below
+/// expects — split out from [`capability_denial_hint`] purely so that shape is testable without a
+/// capability-carrying process to point at.
+fn permitted_caps_from_status(status: &str) -> Option<u64> {
+    let field = status.lines().find(|l| l.starts_with("CapPrm:"))?;
+    u64::from_str_radix(field.split_whitespace().nth(1)?, 16).ok()
+}
+
+#[cfg(test)]
+mod capability_hint_tests {
+    use super::*;
+
+    /// Verbatim from a `cap_sys_nice=ep` process on CachyOS — the case that broke 0.26.0-1.
+    const CAPPED: &str = "Name:\tpunktfunk-host\nUid:\t1000\t1000\t1000\t1000\nCapPrm:\t0000000000800000\nCapEff:\t0000000000800000\n";
+    /// ...and from the same binary with no capability, where the hint must stay silent.
+    const CLEAN: &str = "Name:\tpunktfunk-host\nUid:\t1000\t1000\t1000\t1000\nCapPrm:\t0000000000000000\nCapEff:\t0000000000000000\n";
+
+    #[test]
+    fn parses_the_kernels_permitted_mask() {
+        assert_eq!(permitted_caps_from_status(CAPPED), Some(0x0080_0000));
+        assert_eq!(permitted_caps_from_status(CLEAN), Some(0));
+        // CapPrm is not guaranteed present (older/again-different kernels): stay quiet, never panic.
+        assert_eq!(permitted_caps_from_status("Name:\tx\n"), None);
+        assert_eq!(permitted_caps_from_status("CapPrm:\tzzzz\n"), None);
+        assert_eq!(permitted_caps_from_status("CapPrm:\n"), None);
+    }
+
+    /// A capability-free host must not append the hint — the message it decorates is also printed
+    /// on genuinely missing `.desktop` files, and a spurious "you have capabilities" line would
+    /// send the reader chasing a setcap that was never there. The test process has no capabilities.
+    #[test]
+    fn silent_without_capabilities() {
+        assert_eq!(capability_denial_hint(), "");
+    }
+}
+
 /// Readiness probe: connect to the KWin Wayland socket, roundtrip the registry, and confirm
 /// the privileged `zkde_screencast` global is actually advertised. This is exactly what
 /// [`run`] needs before it can create a virtual output, so a session-bringup script can poll
@@ -1090,7 +1161,8 @@ pub fn probe() -> Result<()> {
              it on the host's .desktop X-KDE-Wayland-Interfaces (install \
              io.unom.Punktfunk.Host.desktop with Exec=/usr/bin/punktfunk-host, then re-login so KWin \
              re-reads it — the grant is cached per-exe on first connect), or set \
-             KWIN_WAYLAND_NO_PERMISSION_CHECKS=1 for the headless test; needs KWin ≥ 6.5.6"
+             KWIN_WAYLAND_NO_PERMISSION_CHECKS=1 for the headless test; needs KWin ≥ 6.5.6{}",
+            capability_denial_hint()
         );
     }
     Ok(())
@@ -1134,7 +1206,9 @@ fn run_existing(
         anyhow!(
             "KWin does not expose zkde_screencast_unstable_v1 to this client — install the host's \
              .desktop (io.unom.Punktfunk.Host.desktop, X-KDE-Wayland-Interfaces) and re-login so \
-             KWin authorizes it, or run KWin with KWIN_WAYLAND_NO_PERMISSION_CHECKS=1 (headless test)"
+             KWin authorizes it, or run KWin with KWIN_WAYLAND_NO_PERMISSION_CHECKS=1 (headless \
+             test){}",
+            capability_denial_hint()
         )
     })?;
 
@@ -1223,7 +1297,9 @@ fn run(
         anyhow!(
             "KWin does not expose zkde_screencast_unstable_v1 to this client — install the host's \
              .desktop (io.unom.Punktfunk.Host.desktop, X-KDE-Wayland-Interfaces) and re-login so \
-             KWin authorizes it, or run KWin with KWIN_WAYLAND_NO_PERMISSION_CHECKS=1 (headless test)"
+             KWin authorizes it, or run KWin with KWIN_WAYLAND_NO_PERMISSION_CHECKS=1 (headless \
+             test){}",
+            capability_denial_hint()
         )
     })?;
 

crates/pf-vdisplay/src/vdisplay/windows/manager.rs

@@ -299,16 +299,21 @@ struct Pinger {
 /// The manager's control-device cache. Reopenable: a driver upgrade / WUDFHost restart kills the
 /// cached handle (every IOCTL fails with a gone-class code forever), so such a failure RETIRES it and
 /// the next [`VirtualDisplayManager::ensure_device`] reopens the (new) device interface, re-running
-/// the version handshake. Retired handles are deliberately kept alive — never closed — for the
-/// process lifetime: the pinger/linger threads and every capturer's `ChannelBroker` hold BARE
-/// `HANDLE` copies whose soundness contract is "never closed"; a retired handle only ever FAILS
-/// IOCTLs, which every holder already tolerates. Reopens are rare (a driver restart), so the retained
-/// list is bounded in practice.
+/// the version handshake.
+///
+/// Ownership is `Arc` all the way out: every consumer — `acquire`'s IOCTL runs, the pinger/linger
+/// threads, the capture layer's delivery closures — holds its OWN clone across its use, so retiring
+/// here merely drops the manager's reference and the handle CLOSES when the last in-flight user
+/// drains. That close is load-bearing, not housekeeping: an open control handle is exactly what
+/// vetoes the PnP disable/restart the wake-from-sleep recovery leans on (field 2026-08-08 — every
+/// reload REFUSED `Generic failure`; `reset-pf-vdisplay.ps1` stops the whole host service precisely
+/// to get its handles closed, and Arc ownership buys the same release without dying). The previous
+/// contract kept retired handles open for the process lifetime because bare `HANDLE` copies were
+/// smuggled into threads and closures; those copies are gone, and nothing may rely on a dead
+/// handle staying open again.
 #[derive(Default)]
 struct DeviceSlot {
     current: Option<Arc<OwnedHandle>>,
-    /// Never dropped — see the type doc (bare-`HANDLE` holders rely on no-close).
-    retired: Vec<Arc<OwnedHandle>>,
     /// `CLEAR_ALL` (crashed-host orphan reap) runs only on the FIRST open of the process; a reopen
     /// races sessions this process still considers live and must not raze them.
     opened_once: bool,
@@ -397,11 +402,6 @@ pub fn vdm() -> &'static VirtualDisplayManager {
         .expect("VirtualDisplayManager used before a backend initialised it")
 }
 
-/// The live pf-vdisplay control-device handle, for the IDD-push capturer's sealed-channel delivery
-/// (`IOCTL_SET_FRAME_CHANNEL`). Safe to hand out as a bare `HANDLE`: cached handles are never closed
-/// for the process lifetime — a dead one is RETIRED (kept alive, see [`DeviceSlot`]), so a stale copy
-/// can only fail IOCTLs, never dangle. `None` before the first backend open — impossible for a
-/// capturer, which only exists on a monitor the manager created.
 /// Can this host's pf-vdisplay driver run the v5 hardware-cursor channel? Reads the
 /// handshake-latched protocol version, opening the control device once if no session has
 /// opened it yet this service run (the same open every session performs anyway) — so the
@@ -421,7 +421,13 @@ pub fn hw_cursor_capable() -> bool {
     m.driver_proto.load(Ordering::Relaxed) >= 5
 }
 
-pub fn control_device_handle() -> Option<HANDLE> {
+/// The live pf-vdisplay control device, for the IDD-push capturer's sealed-channel delivery
+/// (`IOCTL_SET_FRAME_CHANNEL`) — an `Arc` clone the caller (and every closure it builds) holds for
+/// as long as it may issue IOCTLs: the handle stays open while any holder lives and closes when the
+/// last drains, which is what lets the wake-from-sleep recovery's PnP disable proceed once the
+/// manager retires it (see [`DeviceSlot`]). `None` before the first backend open — impossible for a
+/// capturer, which only exists on a monitor the manager created.
+pub fn control_device_handle() -> Option<Arc<OwnedHandle>> {
     VDM.get().and_then(VirtualDisplayManager::device_handle)
 }
 
@@ -497,17 +503,28 @@ fn is_device_gone(e: &anyhow::Error) -> bool {
     GONE.contains(&w.code().0)
 }
 
+/// The transient raw `HANDLE` view of an Arc-held control device, for the backend IOCTL surface.
+/// Sound only while the `Arc` it borrows from is held — which the borrow makes structural: every
+/// use site necessarily has the owning clone alive across the call, so a concurrent retire (which
+/// now really closes the handle once its users drain — see [`DeviceSlot`]) can never close it
+/// mid-IOCTL.
+fn dev_raw(dev: &OwnedHandle) -> HANDLE {
+    HANDLE(dev.as_raw_handle())
+}
+
 impl VirtualDisplayManager {
     pub(crate) fn backend_name(&self) -> &'static str {
         self.driver.name()
     }
 
     /// Open + cache the control device; REOPEN when a gone-classified failure retired the cached one
-    /// (driver upgrade / WUDFHost restart). The `device` mutex serializes racing opens.
-    fn ensure_device(&self) -> Result<HANDLE> {
+    /// (driver upgrade / WUDFHost restart). The `device` mutex serializes racing opens. Returns an
+    /// `Arc` clone the caller holds across every IOCTL it derives from it — a concurrent retire then
+    /// drops only the manager's reference and closes nothing under the caller (see [`DeviceSlot`]).
+    fn ensure_device(&self) -> Result<Arc<OwnedHandle>> {
         let mut slot = self.device.lock().unwrap();
         if let Some(d) = &slot.current {
-            return Ok(HANDLE(d.as_raw_handle()));
+            return Ok(d.clone());
         }
         let reap = !slot.opened_once;
         claim_instance()?;
@@ -519,35 +536,33 @@ impl VirtualDisplayManager {
         slot.opened_once = true;
         self.watchdog_s.store(watchdog_s, Ordering::Relaxed);
         self.driver_proto.store(driver_proto, Ordering::Relaxed);
-        let raw = HANDLE(handle.as_raw_handle());
-        slot.current = Some(Arc::new(handle));
+        let dev = Arc::new(handle);
+        slot.current = Some(dev.clone());
         if !reap {
             tracing::info!("virtual-display control device reopened (retired handle replaced)");
         }
-        Ok(raw)
+        Ok(dev)
     }
 
-    /// The live control handle for the pinger/linger threads. `None` before the first acquire opened
-    /// it, or between a retire and the next reopen.
-    fn device_handle(&self) -> Option<HANDLE> {
-        self.device
-            .lock()
-            .unwrap()
-            .current
-            .as_ref()
-            .map(|d| HANDLE(d.as_raw_handle()))
+    /// The live control device for the pinger/linger threads — an `Arc` clone the caller holds
+    /// across its IOCTLs. `None` before the first acquire opened it, or between a retire and the
+    /// next reopen.
+    fn device_handle(&self) -> Option<Arc<OwnedHandle>> {
+        self.device.lock().unwrap().current.clone()
     }
 
-    /// Retire the cached control handle after a gone-classified IOCTL failure. The handle is retained
-    /// un-closed (see [`DeviceSlot`]); the next [`ensure_device`](Self::ensure_device) reopens the
-    /// (new) device interface and re-runs the version handshake.
+    /// Retire the cached control handle after a gone-classified IOCTL failure: drop the manager's
+    /// reference, so the handle CLOSES once the last in-flight user drains (see [`DeviceSlot`]) —
+    /// the release the wake-from-sleep recovery needs before it can cycle the adapter devnode. The
+    /// next [`ensure_device`](Self::ensure_device) reopens the (new) device interface and re-runs
+    /// the version handshake.
     fn invalidate_device(&self, why: &anyhow::Error) {
         let mut slot = self.device.lock().unwrap();
-        if let Some(cur) = slot.current.take() {
+        if slot.current.take().is_some() {
             tracing::warn!(
-                "virtual-display control device retired — reopening on next use (cause: {why:#})"
+                "virtual-display control device retired — closes when its last user drains, \
+                 reopening on next use (cause: {why:#})"
             );
-            slot.retired.push(cur);
         }
     }
 
@@ -620,11 +635,11 @@ impl VirtualDisplayManager {
                     old_target,
                     "IDD-push reconnect — preempting the kept (lingering/pinned) monitor, recreating a fresh one"
                 );
-                // SAFETY: `teardown_removed` requires `dev` to be a valid control handle; `dev` is the
-                // value `ensure_device()` returned above (cached handles are never closed — a dead one
-                // is retired, kept alive; see `DeviceSlot`). `mon` was just removed from the map, so it
+                // SAFETY: `teardown_removed` requires `dev` to be a valid control handle; the `dev`
+                // Arc `ensure_device()` returned above is held across this call, so the handle stays
+                // open even against a concurrent retire. `mon` was just removed from the map, so it
                 // is exclusively owned here — no aliasing.
-                unsafe { self.teardown_removed(dev, &mut inner, mon) };
+                unsafe { self.teardown_removed(dev_raw(&dev), &mut inner, mon) };
                 // Let the OS finish the ASYNC monitor departure before the next ADD; a back-to-back
                 // REMOVE→ADD races the teardown and the ADD IOCTL is rejected under reconnect churn.
                 // Verified-state wait, ceiling = the old fixed 400 ms settle (latency plan P0.3).
@@ -657,11 +672,11 @@ impl VirtualDisplayManager {
                     wudf_pid = mon.wudf_pid,
                     "virtual monitor's WUDFHost is gone — preempting the dead monitor, recreating"
                 );
-                // SAFETY: `teardown_removed` requires a valid control handle; `dev` is the value
-                // `ensure_device()` returned above (cached handles are never closed — a dead one is
-                // retired, kept alive; see `DeviceSlot`). `mon` was just removed from the map, so it
+                // SAFETY: `teardown_removed` requires a valid control handle; the `dev` Arc
+                // `ensure_device()` returned above is held across this call, so the handle stays
+                // open even against a concurrent retire. `mon` was just removed from the map, so it
                 // is exclusively owned here — no aliasing.
-                unsafe { self.teardown_removed(dev, &mut inner, mon) };
+                unsafe { self.teardown_removed(dev_raw(&dev), &mut inner, mon) };
                 // Same async-departure settle as the reconnect preempt above (verified wait, P0.3).
                 let _ = wait_target_departed(old_target, Duration::from_millis(400));
             }
@@ -693,9 +708,10 @@ impl VirtualDisplayManager {
                         else {
                             unreachable!("just matched Active");
                         };
-                        // SAFETY: `dev` is the handle `ensure_device()` returned above; the CCD
-                        // waits inside run under the held `state` lock (this fn's discipline).
-                        match unsafe { self.resize_in_place(dev, mon, mode) } {
+                        // SAFETY: the `dev` Arc `ensure_device()` returned above is held across
+                        // this call (so the handle stays open); the CCD waits inside run under
+                        // the held `state` lock (this fn's discipline).
+                        match unsafe { self.resize_in_place(dev_raw(&dev), mon, mode) } {
                             Ok(()) => {
                                 // Same join semantics as the re-arrival: +1 ref for the new
                                 // (build-then-drop overlap) lease; `gen` untouched, so the old
@@ -734,10 +750,11 @@ impl VirtualDisplayManager {
                 let Some(SlotState::Active { mon, refs }) = inner.slots.remove(&slot) else {
                     unreachable!("just matched Active");
                 };
-                // SAFETY: `dev` is the handle `ensure_device()` returned above; `re_add` touches the
-                // live topology under the held `state` lock. `mon` is owned here (removed from the map).
+                // SAFETY: the `dev` Arc `ensure_device()` returned above is held across this call
+                // (so the handle stays open); `re_add` touches the live topology under the held
+                // `state` lock. `mon` is owned here (removed from the map).
                 let new_mon = match unsafe {
-                    self.re_add(dev, &mut inner, slot, &mon, mode, client_hdr)
+                    self.re_add(dev_raw(&dev), &mut inner, slot, &mon, mode, client_hdr)
                 } {
                     ReAdd::Arrived(m) => *m,
                     ReAdd::RolledBack {
@@ -815,11 +832,11 @@ impl VirtualDisplayManager {
         }
 
         // The slot is empty: create a fresh monitor for it.
-        // SAFETY: `create_monitor` requires `dev` to be a valid control handle; `dev` is the handle
-        // `ensure_device()` returned above (cached handles are never closed — a dead one is retired,
-        // kept alive; see `DeviceSlot`), and we hold the `state` lock.
+        // SAFETY: `create_monitor` requires `dev` to be a valid control handle; the `dev` Arc
+        // `ensure_device()` returned above is held across this call (so the handle stays open even
+        // against a concurrent retire), and we hold the `state` lock.
         let mon = match unsafe {
-            self.create_monitor(dev, mode, slot, client_hdr, hw_cursor, &mut inner)
+            self.create_monitor(dev_raw(&dev), mode, slot, client_hdr, hw_cursor, &mut inner)
         } {
             // The cached device died under us (driver upgrade / WUDFHost restart, detected only
             // now — e.g. the host sat idle past the pinger-less window). Retire it, reopen, and
@@ -831,9 +848,18 @@ impl VirtualDisplayManager {
                 tracing::info!(
                     "virtual-display control device reopened — retrying the monitor create"
                 );
-                // SAFETY: as above — `dev` is the handle the reopening `ensure_device` just
-                // returned, and the `state` lock is still held.
-                unsafe { self.create_monitor(dev, mode, slot, client_hdr, hw_cursor, &mut inner)? }
+                // SAFETY: as above — the `dev` Arc the reopening `ensure_device` just returned is
+                // held across this call, and the `state` lock is still held.
+                unsafe {
+                    self.create_monitor(
+                        dev_raw(&dev),
+                        mode,
+                        slot,
+                        client_hdr,
+                        hw_cursor,
+                        &mut inner,
+                    )?
+                }
             }
             r => r?,
         };
@@ -887,13 +913,12 @@ impl VirtualDisplayManager {
             let mut warned = false;
             while !stop_t.load(Ordering::Relaxed) {
                 if let Some(h) = vdm().device_handle() {
-                    // SAFETY: `ping` requires `dev` to be a valid control handle. `h` is from
-                    // `device_handle()` (the `Some` branch) — cached handles are NEVER closed for the
-                    // process lifetime (a dead one is retired, kept alive; see `DeviceSlot`), so the
-                    // handle stays valid for this call even if it was retired concurrently — at worst
-                    // the IOCTL fails. The pinger thread only spins while the `&'static` manager
-                    // singleton lives.
-                    match unsafe { vdm().driver.ping(h) } {
+                    // SAFETY: `ping` requires `dev` to be a valid control handle. The `h` Arc from
+                    // `device_handle()` is held across this call, so the handle stays open even if
+                    // it is retired concurrently — at worst the IOCTL fails (the retire drops only
+                    // the manager's reference; see `DeviceSlot`). The pinger thread only spins
+                    // while the `&'static` manager singleton lives.
+                    match unsafe { vdm().driver.ping(dev_raw(&h)) } {
                         Ok(()) => warned = false,
                         Err(e) if is_device_gone(&e) => {
                             // The device itself is gone (driver upgrade / WUDFHost restart) — pings
@@ -1897,12 +1922,11 @@ impl VirtualDisplayManager {
                         slot,
                         "virtual-display: last session left (deliberate quit) — tearing down now, linger skipped"
                     );
-                    // SAFETY: `teardown_removed` requires `dev` to be the live control handle; `dev`
-                    // is the cached process-lifetime `OwnedHandle` from `device_handle()` (the `Some`
-                    // checked above; cached handles are never closed — a dead one is retired, kept
-                    // alive). `mon` was moved out of the map under the `state` lock, so it is
-                    // exclusively owned here — no aliasing.
-                    unsafe { self.teardown_removed(dev, &mut inner, mon) };
+                    // SAFETY: `teardown_removed` requires `dev` to be the live control handle; the
+                    // `dev` Arc from `device_handle()` (the `Some` checked above) is held across
+                    // this call, so the handle stays open. `mon` was moved out of the map under the
+                    // `state` lock, so it is exclusively owned here — no aliasing.
+                    unsafe { self.teardown_removed(dev_raw(&dev), &mut inner, mon) };
                 }
                 None => {
                     inner.slots.insert(
@@ -1980,10 +2004,10 @@ impl VirtualDisplayManager {
                             "IDD-push setup: force-preempting the stuck-Active prior monitor (its IddCx swap-chain is dead)"
                         );
                         // SAFETY: `teardown_removed` requires `dev` to be the live control handle;
-                        // `dev` is the cached process-lifetime `OwnedHandle` from `device_handle()`
-                        // (the `Some` checked above). `mon` was moved out of the map under the
-                        // `state` lock, so it is exclusively owned here — no aliasing.
-                        unsafe { self.teardown_removed(dev, &mut inner, mon) };
+                        // the `dev` Arc from `device_handle()` (the `Some` checked above) is held
+                        // across this call, so the handle stays open. `mon` was moved out of the
+                        // map under the `state` lock, so it is exclusively owned here — no aliasing.
+                        unsafe { self.teardown_removed(dev_raw(&dev), &mut inner, mon) };
                         // Let the OS finish the ASYNC departure before the next ADD (mirrors the
                         // acquire() Lingering-preempt settle).
                         thread::sleep(Duration::from_millis(400));
@@ -2051,11 +2075,12 @@ impl VirtualDisplayManager {
                             // its session. Lock order stays state → device (teardown's invalidate
                             // path), same as every other holder; the pinger takes only the device
                             // lock — no inversion.
-                            // SAFETY: `teardown_removed` requires a valid control handle; `dev` is
-                            // from `self.device_handle()` (cached handles are never closed — a dead
-                            // one is retired, kept alive; see `DeviceSlot`). `mon` was moved out of
-                            // the map under the lock, so it is exclusively owned here.
-                            unsafe { self.teardown_removed(dev, &mut g, mon) };
+                            // SAFETY: `teardown_removed` requires a valid control handle; the `dev`
+                            // Arc from `self.device_handle()` is held across this call, so the
+                            // handle stays open (a concurrent retire drops only the manager's
+                            // reference; see `DeviceSlot`). `mon` was moved out of the map under
+                            // the lock, so it is exclusively owned here.
+                            unsafe { self.teardown_removed(dev_raw(&dev), &mut g, mon) };
                         }
                     }
                 })
@@ -2218,11 +2243,11 @@ impl VirtualDisplayManager {
             if let Some(SlotState::Lingering { mon, .. } | SlotState::Pinned { mon }) =
                 inner.slots.remove(&k)
             {
-                // SAFETY: `teardown_removed` needs a live control handle; `dev` is from
-                // `device_handle()` (cached handles are never closed — a dead one is retired, kept
-                // alive; see `DeviceSlot`). `mon` was moved out of the map under the `state` lock,
-                // so it is exclusively owned here — no aliasing.
-                unsafe { self.teardown_removed(dev, &mut inner, mon) };
+                // SAFETY: `teardown_removed` needs a live control handle; the `dev` Arc from
+                // `device_handle()` is held across this call, so the handle stays open (see
+                // `DeviceSlot`). `mon` was moved out of the map under the `state` lock, so it is
+                // exclusively owned here — no aliasing.
+                unsafe { self.teardown_removed(dev_raw(&dev), &mut inner, mon) };
                 released += 1;
             }
         }

crates/pf-vdisplay/src/vdisplay/windows/pf_vdisplay.rs

@@ -100,14 +100,27 @@ unsafe fn ioctl(h: HANDLE, code: u32, input: &[u8], output: &mut [u8]) -> Result
 /// `reset-pf-vdisplay.ps1` step 2 (proven on-box). Best-effort + idempotent: only NOT-present nodes
 /// (`Status != OK`) are removed, so the LIVE session's monitor (`Status OK`) is never touched; any
 /// failure is logged and swallowed. Returns the number removed.
+///
+/// The outcome is logged UNCONDITIONALLY, as found + removed: the old script counted only removals
+/// and the host spoke only when that count was positive, so a reap whose pnputil never launched and
+/// a box with no ghosts produced byte-identical logs (silence) — the same vacuous-signal family as
+/// the `status=OK` trap [`reload_vdisplay_adapter`] answers — while ghosts ratcheted toward the
+/// wedge with every sleep cycle.
 fn reap_ghost_monitors() -> u32 {
     // Mirrors reset-pf-vdisplay.ps1 step 2. powershell is always present for the SYSTEM service; the
     // matched tokens ('OK', 'punktfunk', the InstanceId) are locale-invariant, so this is safe on a
     // non-English box (unlike a .ps1 *file* read in the machine codepage).
+    //
+    // pnputil is resolved by full path and `$LASTEXITCODE` pre-seeded to failure before every
+    // launch, exactly like the reload path below: a LocalSystem service's PATH need not include
+    // System32 (and a SYSTEM process must not trust PATH anyway — a planted `pnputil.exe` would run
+    // elevated), and the old bare-name call failed INVISIBLY there — `SilentlyContinue` swallowed
+    // the miss, no exit code was written, and the ghosts stayed to wedge `IOCTL_ADD` at 0x80070490.
     const REAP_PS: &str = "$ErrorActionPreference='SilentlyContinue'; \
-        $g = Get-PnpDevice -Class Monitor | Where-Object { $_.Status -ne 'OK' -and $_.FriendlyName -match 'punktfunk' }; \
-        $n = 0; foreach ($d in $g) { pnputil /remove-device $d.InstanceId *> $null; if ($LASTEXITCODE -eq 0) { $n++ } }; \
-        Write-Output $n";
+        $g = @(Get-PnpDevice -Class Monitor | Where-Object { $_.Status -ne 'OK' -and $_.FriendlyName -match 'punktfunk' }); \
+        $pnp = ($env:SystemRoot + '\\System32\\pnputil.exe'); \
+        $n = 0; foreach ($d in $g) { $LASTEXITCODE = 1; if (Test-Path $pnp) { & $pnp /remove-device $d.InstanceId *> $null }; if ($LASTEXITCODE -eq 0) { $n++ } }; \
+        Write-Output ($g.Count.ToString() + ' ' + $n)";
     // Resolve powershell by full path — the LocalSystem service's PATH is not guaranteed to include
     // System32 — with a bare-name fallback.
     let ps = std::env::var("SystemRoot")
@@ -125,17 +138,29 @@ fn reap_ghost_monitors() -> u32 {
         .output()
     {
         Ok(o) => {
-            let n = String::from_utf8_lossy(&o.stdout)
-                .trim()
-                .parse::<u32>()
-                .unwrap_or(0);
-            if n > 0 {
+            let raw = String::from_utf8_lossy(&o.stdout);
+            let Some((found, removed)) = parse_reap_output(&raw) else {
                 tracing::warn!(
-                    reaped = n,
+                    output = %raw.trim(),
+                    "pf-vdisplay: ghost-monitor reap died before reporting — ghost nodes (if any) still pin IddCx monitor slots"
+                );
+                return 0;
+            };
+            if found == 0 {
+                tracing::info!("pf-vdisplay: no ghost (not-present) virtual-monitor nodes to reap");
+            } else if removed < found {
+                tracing::warn!(
+                    found,
+                    removed,
+                    "pf-vdisplay: ghost-monitor reap could NOT remove every ghost node — the leftovers keep pinning IddCx monitor slots toward the 0x80070490 wedge"
+                );
+            } else {
+                tracing::warn!(
+                    reaped = removed,
                     "pf-vdisplay: reaped ghost (not-present) virtual-monitor nodes — IddCx slot-exhaustion prevention"
                 );
             }
-            n
+            removed
         }
         Err(e) => {
             tracing::warn!(error = %e, "pf-vdisplay: ghost-monitor reap could not spawn powershell");
@@ -144,6 +169,18 @@ fn reap_ghost_monitors() -> u32 {
     }
 }
 
+/// Parse [`reap_ghost_monitors`]'s script output — `"<found> <removed>"`. Split out to be testable
+/// without a box, like [`classify_reload_output`]: the field failure this answers was a reap whose
+/// outcome could not be decoded from the log at all, so the decoding is worth pinning down. `None`
+/// = the script died before reporting (callers treat that as "removed nothing", loudly).
+fn parse_reap_output(out: &str) -> Option<(u32, u32)> {
+    let mut it = out.split_whitespace().map(str::parse::<u32>);
+    match (it.next(), it.next()) {
+        (Some(Ok(found)), Some(Ok(removed))) => Some((found, removed)),
+        _ => None,
+    }
+}
+
 /// What an adapter-cycle attempt actually DID — deliberately NOT the devnode's PnP status afterwards.
 /// The old script reported that status, and a device it had failed to touch at all still reads `OK`,
 /// so a no-op cycle was indistinguishable from a real one in the log (field report 2026-08-02: a
@@ -178,6 +215,14 @@ fn reload_vdisplay_adapter() -> AdapterCycle {
     // device description — locale-invariant). Same spawn shape as `reap_ghost_monitors` above; the
     // reported tokens are ours, so parsing them is locale-invariant too.
     //
+    // The selector prefers LIVE devnodes: `Get-PnpDevice` also lists not-present PHANTOMS (an
+    // upgrade/reinstall leftover), and the old `Select-Object -First 1` could hand every recovery
+    // attempt a phantom — whose disable AND restart both fail — while a live node sat unexamined.
+    // A phantom-only state gets its own truthful refusal: no reload lever can revive a devnode
+    // record whose device is GONE; only re-creating the node (reinstall) can. `Present` is the
+    // authoritative bit, with `Status -ne 'Unknown'` as the fallback should it read null; live
+    // `OK` nodes sort ahead of problem-state ones.
+    //
     // Every step that can fail is `-ErrorAction Stop` inside a `try` — the old script ran the whole
     // cycle under `SilentlyContinue` and then reported `(Get-PnpDevice …).Status`, which reports the
     // DEVICE, not the cycle: a disable that was refused left the device untouched, started, and
@@ -188,10 +233,19 @@ fn reload_vdisplay_adapter() -> AdapterCycle {
     // let "never ran" read as "returned 0". Pre-seeding a failure means only a real exit 0 reports a
     // reload. pnputil is resolved by full path — a LocalSystem service's PATH need not include
     // System32.
+    //
+    // The REFUSED line carries the evidence a field log needs to tell the failure modes apart
+    // (2026-08-08: a woken box logged only `REFUSED Generic failure` — the WMI catch-all — leaving
+    // handle-veto vs phantom vs problem-state undecidable): how many devnodes matched and how many
+    // are live, the chosen node's PnP Status + ConfigManager problem code, and the pnputil
+    // /restart-device exit code the old script threw away (3010 = needs a reboot, which is its own
+    // diagnosis).
     const CYCLE_PS: &str = "$ErrorActionPreference='SilentlyContinue'; \
-        $ad = Get-PnpDevice -Class Display | Where-Object { $_.FriendlyName -match 'punktfunk Virtual Display' } | Select-Object -First 1; \
-        if (-not $ad) { Write-Output 'ABSENT'; exit }; \
-        $id = $ad.InstanceId; $err = ''; \
+        $all = @(Get-PnpDevice -Class Display | Where-Object { $_.FriendlyName -match 'punktfunk Virtual Display' }); \
+        if ($all.Count -eq 0) { Write-Output 'ABSENT'; exit }; \
+        $live = @($all | Where-Object { $_.Present -or $_.Status -ne 'Unknown' } | Sort-Object { $_.Status -ne 'OK' }); \
+        if ($live.Count -eq 0) { Write-Output ('REFUSED only phantom (not-present) adapter devnodes remain (' + $all.Count + ') - the device node itself is gone and no reload can revive it; reinstalling the host re-creates it'); exit }; \
+        $ad = $live[0]; $id = $ad.InstanceId; $err = ''; \
         try { \
             Disable-PnpDevice -InstanceId $id -Confirm:$false -ErrorAction Stop; Start-Sleep -Seconds 2; \
             try { Enable-PnpDevice -InstanceId $id -Confirm:$false -ErrorAction Stop } \
@@ -201,9 +255,11 @@ fn reload_vdisplay_adapter() -> AdapterCycle {
         } catch { $err = ($_.Exception.Message -replace '\\s+', ' ') }; \
         $pnp = ($env:SystemRoot + '\\System32\\pnputil.exe'); $LASTEXITCODE = 1; \
         if (Test-Path $pnp) { & $pnp /restart-device $id *> $null }; \
-        if ($LASTEXITCODE -eq 0) { Start-Sleep -Seconds 2; \
+        $rx = $LASTEXITCODE; \
+        if ($rx -eq 0) { Start-Sleep -Seconds 2; \
             Write-Output ('RELOADED restart ' + (Get-PnpDevice -InstanceId $id).Status) } \
-        else { Enable-PnpDevice -InstanceId $id -Confirm:$false; Write-Output ('REFUSED ' + $err) }";
+        else { Enable-PnpDevice -InstanceId $id -Confirm:$false; \
+            Write-Output ('REFUSED devnodes=' + $all.Count + ' live=' + $live.Count + ' status=' + $ad.Status + ' problem=' + $ad.ConfigManagerErrorCode + ' restart_exit=' + $rx + ' ' + $err) }";
     let ps = std::env::var("SystemRoot")
         .map(|r| format!(r"{r}\System32\WindowsPowerShell\v1.0\powershell.exe"))
         .unwrap_or_else(|_| "powershell.exe".to_string());
@@ -1050,10 +1106,12 @@ const BRIEF_RETRY: Duration = Duration::from_secs(3);
 /// them rather than N interleaved ones — each of which tears down the stack the others are waiting
 /// on. The second caller through typically finds the interface already up and returns at once.
 ///
-/// Taken ONLY by [`ensure_available`], which holds no manager lock, and released before the retire
-/// hook below takes the manager's `device` mutex. That is what keeps the lock order one-way:
-/// [`VdisplayDriver::open`] runs *inside* that same `device` mutex, so if it could also take this
-/// lock the two orders would invert and deadlock. It cannot — it never reloads.
+/// Taken ONLY by [`ensure_available`], which holds no manager lock. The lock order is one-way —
+/// `RECOVERY` → `device`: the recovery's handle-release hooks (`invalidate_cached_device`, which
+/// drops the manager's reference so the control handle can CLOSE before the PnP cycle) take the
+/// `device` mutex while this is held. It must stay one-way: [`VdisplayDriver::open`] runs *inside*
+/// that same `device` mutex, so if it could also take this lock the two orders would invert and
+/// deadlock. It cannot — it never reloads.
 static RECOVERY: std::sync::Mutex<()> = std::sync::Mutex::new(());
 
 /// [`is_available`], with self-heal — and with PATIENCE, which is the part that matters after a
@@ -1069,10 +1127,11 @@ pub fn ensure_available() -> Result<()> {
         let _serialize = RECOVERY.lock().unwrap_or_else(|e| e.into_inner());
         wait_for_interface(NOT_READY_GRACE, true)
     };
-    // OUTSIDE the recovery lock, by the ordering contract on `RECOVERY`. A reload tore the driver
-    // stack down and back up, so any control handle a previous session cached is dead by
-    // construction — retire it while we know that for certain, rather than leaving the next session
-    // to discover it by having an IOCTL fail. No-op before any backend opened the device.
+    // A reload tore the driver stack down and back up, so any control handle cached MEANWHILE (a
+    // racing open during the arrival window) is dead by construction — retire it while we know
+    // that for certain, rather than leaving the next session to discover it by having an IOCTL
+    // fail. Usually a no-op now: the recovery path already released the manager's reference
+    // before the reload (the handle-drain that lets the PnP cycle proceed at all).
     if reloaded {
         super::manager::invalidate_cached_device(
             "the pf-vdisplay adapter was reloaded (hostless-zombie recovery)",
@@ -1119,12 +1178,33 @@ fn wait_for_interface(not_ready_grace: Duration, reload: bool) -> (Result<OwnedH
         // Track how long we have seen NOTHING. Reset by any sighting, so a device that flickers
         // between absent and not-ready is treated as the transition it is.
         if probe.is_absent() {
+            if absent_since.is_none() && reload {
+                // First absent sighting on the recovery path: drop the manager's reference to the
+                // (dead) control device NOW, so the ABSENT_SETTLE below doubles as the drain window
+                // for every outstanding `Arc` clone — the handle then actually CLOSES before the
+                // reload runs. An open control handle is exactly what vetoes the PnP disable (and
+                // can wedge the pnputil restart) that the reload leans on; reset-pf-vdisplay.ps1
+                // stops the whole host service to get the same release (field 2026-08-08: every
+                // reload on a woken box came back REFUSED `Generic failure`). Gated on `reload`:
+                // the BRIEF_RETRY caller runs inside the manager's `device` mutex, where taking it
+                // again would deadlock — and that caller never reloads anyway.
+                super::manager::invalidate_cached_device(
+                    "control interface absent — releasing the host's own device handle ahead of a \
+                     possible adapter reload",
+                );
+            }
             absent_since.get_or_insert_with(Instant::now);
         } else {
             absent_since = None;
         }
         let absent_long_enough = absent_since.is_some_and(|t| t.elapsed() >= ABSENT_SETTLE);
         if reload && !reloaded && (absent_long_enough || Instant::now() >= deadline) {
+            // The not-ready path reaches here without the absent-sighting release above — drop the
+            // manager's reference now for the same reason (idempotent: a second call is a no-op).
+            super::manager::invalidate_cached_device(
+                "adapter reload imminent — releasing the host's own device handle (open handles \
+                 veto the PnP cycle)",
+            );
             match reload_vdisplay_adapter() {
                 // No devnode at all — waiting cannot conjure a driver. Fail immediately rather than
                 // burning the arrival window on a box that simply does not have it installed.
@@ -1195,6 +1275,32 @@ mod tests {
         }
     }
 
+    /// A refusal must carry evidence, not just a verdict. The 2026-08-08 field log showed only
+    /// `REFUSED Generic failure` — the WMI catch-all — leaving handle-veto vs phantom vs
+    /// problem-state undecidable from the log. The enriched line's tokens (devnode counts, PnP
+    /// status, problem code, the pnputil restart exit code the old script discarded) must survive
+    /// decoding verbatim, and the phantom-only state must decode as a refusal too — a reload
+    /// cannot revive a devnode record whose device is gone.
+    #[test]
+    fn a_refusal_keeps_its_evidence() {
+        let why = match classify_reload_output(
+            "REFUSED devnodes=2 live=1 status=OK problem=0 restart_exit=3010 Generic failure",
+        ) {
+            AdapterCycle::Refused(why) => why,
+            other => panic!("expected Refused, got {}", variant(&other)),
+        };
+        for token in ["devnodes=2", "live=1", "status=OK", "restart_exit=3010"] {
+            assert!(why.contains(token), "{token} must survive: {why:?}");
+        }
+        assert!(matches!(
+            classify_reload_output(
+                "REFUSED only phantom (not-present) adapter devnodes remain (2) - the device node \
+                 itself is gone and no reload can revive it; reinstalling the host re-creates it"
+            ),
+            AdapterCycle::Refused(why) if why.contains("phantom")
+        ));
+    }
+
     /// The outcomes callers branch on: `NotInstalled` fails a session fast, `Reloaded` earns the
     /// arrival window, and the lever that worked stays visible in the log (`restart` means the
     /// disable was refused and something still holds the device open).
@@ -1226,6 +1332,29 @@ mod tests {
         ));
     }
 
+    /// The reap's outcome must decode losslessly — the field ratchet (0.23→0.25) was a reap whose
+    /// bare-named pnputil never launched under the LocalSystem PATH while the host stayed silent:
+    /// "no ghosts" and "removed nothing" were byte-identical. Found and removed now travel
+    /// separately so a leftover ghost is loud, and the old single-number output (or a powershell
+    /// that died before reporting) must not decode as anything.
+    #[test]
+    fn reap_output_decodes_found_and_removed() {
+        assert_eq!(parse_reap_output("3 3\r\n"), Some((3, 3)));
+        assert_eq!(
+            parse_reap_output("4 0"),
+            Some((4, 0)),
+            "pnputil unlaunchable"
+        );
+        assert_eq!(parse_reap_output("0 0"), Some((0, 0)), "clean box");
+        for dead in ["5", "", "   ", "garbage", "OK"] {
+            assert_eq!(
+                parse_reap_output(dead),
+                None,
+                "{dead:?} is not a reap report"
+            );
+        }
+    }
+
     /// `is_absent` is what decides between WAITING and performing device surgery, so the two states
     /// it separates are pinned here. An interface that is registered but not yet ACTIVE is a devnode
     /// mid-transition — the wake-from-sleep case — and reloading the adapter under it only lengthens

crates/pf-zerocopy/src/imp/mod.rs

@@ -19,7 +19,7 @@ pub mod vkslot;
 pub mod vulkan;
 pub mod worker;
 
-use std::sync::atomic::{AtomicBool, AtomicU32, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicU32, AtomicU64, Ordering};
 
 pub use cuda::DeviceBuffer;
 pub use egl::{DmabufPlane, EglImporter};
@@ -261,56 +261,223 @@ pub fn gpu_import_disabled() -> bool {
 /// operator found `PUNKTFUNK_ZEROCOPY=0` by hand. The host already knows how to encode that
 /// machine — capture just has to stop handing it dmabufs. Latching here is what makes the next
 /// session negotiate CPU frames on its own.
-static RAW_DMABUF_FAILURE_STREAK: AtomicU32 = AtomicU32::new(0);
-static RAW_DMABUF_DISABLED: AtomicBool = AtomicBool::new(false);
 /// Below the encoder's own rebuild budget, so the latch is set before the session it doomed ends.
 const RAW_DMABUF_FAILURE_LATCH: u32 = 3;
 
-/// Record an encoder-side raw-dmabuf import failure. Latches the process-wide disable after
-/// `RAW_DMABUF_FAILURE_LATCH` consecutive failures.
+/// Consecutive capture rebuilds whose dmabuf-only offer never negotiated before the passthrough is
+/// latched off. **2 = one retry**, deliberately: each failed negotiation costs a ~10 s stall, so a
+/// larger budget is paid by the user in dead air. One retry is enough to survive a compositor
+/// caught mid-restart, which is the transient this exists for; a compositor that genuinely never
+/// accepts keeps the same capture identity, so its streak accumulates and it latches on the second
+/// try — one extra stall versus the old behaviour, once per host lifetime.
+const RAW_DMABUF_NEGOTIATION_LATCH: u32 = 2;
+
+/// The raw-dmabuf passthrough's off-switch — **two causes with two different lifetimes**, which is
+/// the whole point of this type.
+///
+/// They used to share one `AtomicBool`, so the cheap recoverable cause (a negotiation that timed
+/// out, possibly because the compositor was mid-restart) was as permanent as the expensive
+/// unrecoverable one (an encoder that cannot import what this compositor allocates). Once either
+/// fired, EVERY later session on the host captured CPU frames until the process was restarted —
+/// including sessions against a completely different compositor and node, which had never failed
+/// at anything.
+///
+/// * **Import failures stay sticky.** A driver that will not take what the compositor allocates
+///   refuses identically on every retry, and the encode-stall recovery above cannot tell that from
+///   a transient — it rebuilt the same failing encoder five times and then ended the session, on
+///   every connection, forever. That is what this latch was born to stop, and it must keep
+///   stopping it.
+/// * **Negotiation timeouts get a retry budget** ([`RAW_DMABUF_NEGOTIATION_LATCH`]).
+/// * **Both are keyed to a capture identity.** A new node id — a fresh virtual output, the
+///   Bazzite Gaming↔Desktop switch, a compositor restart — is a genuinely different question, so
+///   it earns a fresh dmabuf attempt instead of inheriting a verdict about something else.
+///
+/// Atomics rather than a lock because [`note_import_ok`](Self::note_import_ok) is on the per-frame
+/// import path; everything else here runs at pipeline build or on failure.
+#[derive(Debug)]
+pub struct RawDmabufLatch {
+    import_streak: AtomicU32,
+    import_latched: AtomicBool,
+    negotiation_streak: AtomicU32,
+    negotiation_latched: AtomicBool,
+    /// The capture identity the counters above describe. `u64::MAX` = nothing observed yet (a real
+    /// identity is a node id, so it can never collide with the sentinel).
+    identity: AtomicU64,
+}
+
+/// Nothing observed yet — distinct from any real capture identity.
+const NO_IDENTITY: u64 = u64::MAX;
+
+impl RawDmabufLatch {
+    pub const fn new() -> Self {
+        RawDmabufLatch {
+            import_streak: AtomicU32::new(0),
+            import_latched: AtomicBool::new(false),
+            negotiation_streak: AtomicU32::new(0),
+            negotiation_latched: AtomicBool::new(false),
+            identity: AtomicU64::new(NO_IDENTITY),
+        }
+    }
+
+    /// Whether the raw-dmabuf passthrough is currently off, for either cause.
+    pub fn disabled(&self) -> bool {
+        self.import_latched.load(Ordering::Relaxed)
+            || self.negotiation_latched.load(Ordering::Relaxed)
+    }
+
+    /// Tell the latch which capture is about to be built. A DIFFERENT capture from the one the
+    /// current verdict was formed against clears every counter and both latches, so the new
+    /// pipeline earns a fresh dmabuf attempt.
+    ///
+    /// Returns `true` only when that clear actually **re-armed something** — i.e. the identity
+    /// changed *and* a latch was set. Deliberately not "the identity changed": every session on a
+    /// fresh virtual output changes it, and a caller that logged on that would print a re-arm line
+    /// on every healthy session open, which is noise. `true` means "this capture would have been
+    /// forced to CPU by an earlier capture's verdict, and no longer is".
+    ///
+    /// Call this BEFORE reading [`disabled`](Self::disabled) for a negotiation decision, or the
+    /// decision is made against the previous capture's verdict.
+    pub fn observe_capture(&self, identity: u64) -> bool {
+        if self.identity.swap(identity, Ordering::Relaxed) == identity {
+            return false;
+        }
+        let was_latched = self.disabled();
+        self.import_streak.store(0, Ordering::Relaxed);
+        self.import_latched.store(false, Ordering::Relaxed);
+        self.negotiation_streak.store(0, Ordering::Relaxed);
+        self.negotiation_latched.store(false, Ordering::Relaxed);
+        was_latched
+    }
+
+    /// Record an encoder-side raw-dmabuf import failure. Returns `true` if this failure is the one
+    /// that latched the passthrough off.
+    pub fn note_import_failure(&self) -> Option<u32> {
+        let streak = self.import_streak.fetch_add(1, Ordering::Relaxed) + 1;
+        (streak >= RAW_DMABUF_FAILURE_LATCH && !self.import_latched.swap(true, Ordering::Relaxed))
+            .then_some(streak)
+    }
+
+    /// Record a raw dmabuf that imported and encoded — resets the failure streak. The per-frame
+    /// hot path, hence a single relaxed store.
+    ///
+    /// Deliberately does NOT clear `import_latched`: once the latch fires, capture has already
+    /// moved to CPU frames, so there are no more dmabuf imports to succeed. Only a new capture
+    /// identity clears it.
+    pub fn note_import_ok(&self) {
+        self.import_streak.store(0, Ordering::Relaxed);
+    }
+
+    /// Record a capture rebuild whose dmabuf-only offer never negotiated. Returns `Some(streak)`
+    /// if this is the failure that latched the passthrough off, `None` while retries remain.
+    pub fn note_negotiation_timeout(&self) -> Option<u32> {
+        let streak = self.negotiation_streak.fetch_add(1, Ordering::Relaxed) + 1;
+        (streak >= RAW_DMABUF_NEGOTIATION_LATCH
+            && !self.negotiation_latched.swap(true, Ordering::Relaxed))
+        .then_some(streak)
+    }
+
+    /// Record a capture whose dmabuf offer DID negotiate — the retry budget is per consecutive
+    /// run of failures, so a success spends none of it.
+    pub fn note_negotiation_ok(&self) {
+        self.negotiation_streak.store(0, Ordering::Relaxed);
+    }
+
+    /// Diagnostic for the session-open line: which cause (if any) currently holds it off.
+    pub fn state(&self) -> &'static str {
+        match (
+            self.import_latched.load(Ordering::Relaxed),
+            self.negotiation_latched.load(Ordering::Relaxed),
+        ) {
+            (true, true) => "latched: encoder-import + negotiation",
+            (true, false) => "latched: encoder-import failures",
+            (false, true) => "latched: negotiation timeouts",
+            (false, false) => "live",
+        }
+    }
+}
+
+impl Default for RawDmabufLatch {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+static RAW_DMABUF: RawDmabufLatch = RawDmabufLatch::new();
+
+/// Record an encoder-side raw-dmabuf import failure. Latches the passthrough off after
+/// `RAW_DMABUF_FAILURE_LATCH` consecutive failures, until the capture identity changes.
 pub fn note_raw_dmabuf_import_failure(reason: &str) {
-    let streak = RAW_DMABUF_FAILURE_STREAK.fetch_add(1, Ordering::Relaxed) + 1;
-    if streak >= RAW_DMABUF_FAILURE_LATCH && !RAW_DMABUF_DISABLED.swap(true, Ordering::Relaxed) {
+    if let Some(streak) = RAW_DMABUF.note_import_failure() {
         tracing::error!(
             streak,
             reason,
-            "zero-copy raw-dmabuf passthrough disabled for this host process: the encoder failed \
-             to import the compositor's dmabuf {streak} times in a row — captures fall back to the \
-             CPU path (slower, but this host could not stream at all otherwise)"
+            "zero-copy raw-dmabuf passthrough disabled: the encoder failed to import the \
+             compositor's dmabuf {streak} times in a row — captures fall back to the CPU path \
+             (slower, but this host could not stream at all otherwise). A new capture (different \
+             node / compositor) clears this."
         );
     }
 }
 
 /// Record a raw dmabuf that imported and encoded — resets the failure streak.
 pub fn note_raw_dmabuf_import_ok() {
-    RAW_DMABUF_FAILURE_STREAK.store(0, Ordering::Relaxed);
+    RAW_DMABUF.note_import_ok();
 }
 
 /// Latch the raw-dmabuf passthrough off because its dmabuf-only *offer never negotiated* — the
-/// CAPTURE-side counterpart to [`note_raw_dmabuf_import_failure`]'s encoder-side streak. One
-/// timeout is conclusive for this offer (a compositor that cannot allocate the requested
-/// LINEAR/modifier BGRx dmabuf refuses it identically on every retry), so there is no streak to
-/// count: the next capture skips the passthrough and negotiates SHM/CPU instead of re-running the
-/// same 10 s timeout on every reconnect.
+/// CAPTURE-side counterpart to [`note_raw_dmabuf_import_failure`]'s encoder-side streak.
+///
+/// Unlike the import streak this gets a retry budget: the offer can time out because the
+/// compositor was mid-restart rather than because it will never accept, and the old behaviour
+/// (one timeout = CPU capture for the rest of the host's life, for every compositor and every
+/// node) turned a transient into a permanent downgrade nobody could see.
 ///
 /// Scoped deliberately. This used to be `note_vaapi_dmabuf_failed`, which fed [`enabled`] and so
-/// disabled ALL zero-copy host-wide — see [`enabled`]. `RAW_DMABUF_DISABLED` gates only the
-/// raw-passthrough decision, so the EGL→CUDA importer that a later NVENC session builds is
-/// untouched.
+/// disabled ALL zero-copy host-wide — see [`enabled`]. It gates only the raw-passthrough decision,
+/// so the EGL→CUDA importer that a later NVENC session builds is untouched.
 pub fn note_raw_dmabuf_negotiation_failed() {
-    if !RAW_DMABUF_DISABLED.swap(true, Ordering::Relaxed) {
-        tracing::warn!(
-            "zero-copy raw-dmabuf passthrough disabled for this host process: the compositor never \
-             accepted the dmabuf-only capture offer, so later captures negotiate the CPU path \
-             instead of repeating that timeout (the EGL→CUDA import path is NOT affected)"
-        );
+    match RAW_DMABUF.note_negotiation_timeout() {
+        Some(streak) => tracing::warn!(
+            streak,
+            "zero-copy raw-dmabuf passthrough disabled: the compositor did not accept the \
+             dmabuf-only capture offer {streak} builds in a row, so later captures negotiate the \
+             CPU path instead of repeating that timeout (the EGL→CUDA import path is NOT \
+             affected). A new capture (different node / compositor) clears this."
+        ),
+        None => tracing::warn!(
+            "the compositor did not accept the dmabuf-only capture offer — retrying dmabuf on the \
+             next capture build before giving up on it"
+        ),
     }
 }
 
-/// True once repeated encoder import failures latched the raw-dmabuf passthrough off (see
-/// [`note_raw_dmabuf_import_failure`]).
+/// Record a capture whose dmabuf offer negotiated — spends none of the retry budget.
+pub fn note_raw_dmabuf_negotiation_ok() {
+    RAW_DMABUF.note_negotiation_ok();
+}
+
+/// Tell the latch which capture is about to be built, so a verdict formed against a DIFFERENT
+/// compositor/node is not inherited. Returns `true` if a latch was cleared by the change.
+pub fn note_raw_dmabuf_capture(identity: u64) -> bool {
+    let cleared = RAW_DMABUF.observe_capture(identity);
+    if cleared {
+        tracing::info!(
+            identity,
+            "zero-copy raw-dmabuf passthrough re-armed: this is a different capture from the one \
+             that failed, so it gets a fresh dmabuf attempt"
+        );
+    }
+    cleared
+}
+
+/// True while either cause holds the raw-dmabuf passthrough off (see [`RawDmabufLatch`]).
 pub fn raw_dmabuf_import_disabled() -> bool {
-    RAW_DMABUF_DISABLED.load(Ordering::Relaxed)
+    RAW_DMABUF.disabled()
+}
+
+/// Which cause holds the passthrough off, for the session-open diagnostic line.
+pub fn raw_dmabuf_latch_state() -> &'static str {
+    RAW_DMABUF.state()
 }
 
 /// The EGL→CUDA twin of the raw-passthrough negotiation latch: the capture advertised the GPU
@@ -564,4 +731,131 @@ mod tests {
         note_gpu_import_death(); // third consecutive death
         assert!(gpu_import_disabled());
     }
+
+    // ---- PW3: the raw-dmabuf latch's two lifetimes ------------------------------------------
+    //
+    // Against a LOCAL `RawDmabufLatch`, never the process-wide static: these assertions are about
+    // the state machine, and sharing one global across a test binary's threads is how a latch test
+    // becomes order-dependent.
+
+    /// The expensive cause stays sticky. A driver that cannot import what this compositor
+    /// allocates refuses identically every time, and the encode-stall recovery cannot tell that
+    /// from a transient — this latch is what stops it rebuilding the same doomed encoder forever.
+    #[test]
+    fn import_failures_latch_and_stay_latched() {
+        let l = RawDmabufLatch::new();
+        assert!(!l.disabled());
+        assert_eq!(l.note_import_failure(), None); // 1
+        assert_eq!(l.note_import_failure(), None); // 2
+        assert!(!l.disabled(), "must not latch before the streak completes");
+        assert_eq!(l.note_import_failure(), Some(3));
+        assert!(l.disabled());
+        // Only the FIRST crossing reports, so the error line cannot repeat per frame.
+        assert_eq!(l.note_import_failure(), None);
+        // A success resets the streak but must NOT unlatch: once capture moved to CPU frames there
+        // are no more dmabuf imports, so an "ok" here would be about something else entirely.
+        l.note_import_ok();
+        assert!(l.disabled());
+    }
+
+    /// A run of failures broken by a success spends none of the budget — the streak is
+    /// consecutive-only, which is what makes an occasional failure survivable.
+    #[test]
+    fn a_success_breaks_the_import_streak() {
+        let l = RawDmabufLatch::new();
+        l.note_import_failure();
+        l.note_import_failure();
+        l.note_import_ok();
+        assert_eq!(l.note_import_failure(), None, "streak restarted at 1");
+        assert_eq!(l.note_import_failure(), None);
+        assert!(!l.disabled());
+        assert_eq!(l.note_import_failure(), Some(3));
+    }
+
+    /// The cheap cause gets a retry. This is the behaviour change PW3 exists for: one timeout used
+    /// to mean CPU capture for the rest of the host's life, on every compositor and every node.
+    #[test]
+    fn a_negotiation_timeout_is_retried_before_it_latches() {
+        let l = RawDmabufLatch::new();
+        assert_eq!(l.note_negotiation_timeout(), None, "first one retries");
+        assert!(
+            !l.disabled(),
+            "the next capture build must still be allowed to try dmabuf"
+        );
+        assert_eq!(l.note_negotiation_timeout(), Some(2));
+        assert!(l.disabled());
+        assert_eq!(l.note_negotiation_timeout(), None, "reports once");
+    }
+
+    /// A capture that negotiates credits the budget back, so a compositor that fails once and then
+    /// works never accumulates its way to a latch across an evening of reconnects.
+    #[test]
+    fn a_negotiated_capture_credits_the_retry_budget() {
+        let l = RawDmabufLatch::new();
+        for _ in 0..10 {
+            assert_eq!(l.note_negotiation_timeout(), None);
+            l.note_negotiation_ok();
+        }
+        assert!(!l.disabled());
+    }
+
+    /// A different capture is a different question. New node id (fresh virtual output, compositor
+    /// restart, the Bazzite Gaming↔Desktop switch) clears BOTH causes — the same capture does not.
+    #[test]
+    fn a_new_capture_identity_clears_the_latch_and_the_same_one_does_not() {
+        let l = RawDmabufLatch::new();
+        // Nothing is latched yet, so observing a new capture re-arms NOTHING — that is what the
+        // return value means, and it is why a healthy session open logs no re-arm line.
+        assert!(
+            !l.observe_capture(7),
+            "nothing was latched, nothing re-armed"
+        );
+        assert!(!l.observe_capture(7), "same capture, no clear");
+        for _ in 0..RAW_DMABUF_FAILURE_LATCH {
+            l.note_import_failure();
+        }
+        assert!(l.disabled());
+        assert!(
+            !l.observe_capture(7),
+            "the SAME capture must keep its verdict — this is the 10s-stall hazard the latch exists for"
+        );
+        assert!(l.disabled());
+        assert!(l.observe_capture(9), "a different node re-arms it");
+        assert!(!l.disabled());
+        // ...and the streaks reset with it, so the fresh attempt gets a full budget.
+        assert_eq!(l.note_import_failure(), None);
+    }
+
+    /// The negotiation latch is keyed the same way — a compositor restart must not inherit the
+    /// previous one's timeout verdict.
+    #[test]
+    fn a_new_capture_identity_clears_the_negotiation_latch_too() {
+        let l = RawDmabufLatch::new();
+        l.observe_capture(1);
+        l.note_negotiation_timeout();
+        l.note_negotiation_timeout();
+        assert!(l.disabled());
+        assert!(l.observe_capture(2));
+        assert!(!l.disabled());
+    }
+
+    /// The session-open line has to name WHICH cause holds it off — "cpu because nothing here
+    /// does dmabuf" and "cpu because something failed earlier" are different bugs.
+    #[test]
+    fn latch_state_names_the_cause() {
+        let l = RawDmabufLatch::new();
+        assert_eq!(l.state(), "live");
+        l.note_negotiation_timeout();
+        l.note_negotiation_timeout();
+        assert_eq!(l.state(), "latched: negotiation timeouts");
+        let l = RawDmabufLatch::new();
+        for _ in 0..RAW_DMABUF_FAILURE_LATCH {
+            l.note_import_failure();
+        }
+        assert_eq!(l.state(), "latched: encoder-import failures");
+        for _ in 0..RAW_DMABUF_NEGOTIATION_LATCH {
+            l.note_negotiation_timeout();
+        }
+        assert_eq!(l.state(), "latched: encoder-import + negotiation");
+    }
 }

crates/punktfunk-core/src/audio.rs

@@ -497,6 +497,31 @@ const SHRINK_QUIET_MS: u32 = 30_000;
 /// The same, while the A/V sync loop is actively asking for a shallower ring — see the branch in
 /// [`JitterPolicy::note_read`] that selects between them.
 const SHRINK_QUIET_SYNC_MS: u32 = 5_000;
+/// Post-read depth below which a served callback counts as a NEAR-MISS: the device got its
+/// samples, but less than one protocol frame was left in hand, so the next callback starves
+/// unless a packet lands inside one frame time. On a healthy link the post-read depth hovers a
+/// whole target above this, which is what makes a near-miss evidence of real delivery jitter —
+/// the same evidence as an underrun, except nobody heard it yet.
+const NEAR_MISS_MARGIN_MS: u32 = FRAME_MS;
+/// How long a shrink remains a PROBE, in consumed audio: an underrun or near-miss inside this
+/// window means the shrink was wrong, and the previous target is restored at once instead of
+/// being re-learned three audible underruns at a time.
+const SHRINK_PROBE_MS: u32 = 5_000;
+/// A ring is HOLLOW when its depth AVERAGE sits this far below the target: the target promises a
+/// depth the ring does not actually hold. Growth only ever raises the promise — the one thing
+/// that re-banks real depth is a re-prime — so an underrun in a hollow ring re-primes AT ONCE:
+/// the click has already happened, and spending it on the whole refill is strictly better than
+/// riding the knife edge and paying a click per bunching period indefinitely, which is what the
+/// consecutive-empties hysteresis alone converges to. A full ring's underrun (one packet a few
+/// ms late) is nowhere near hollow and keeps the hysteresis.
+const DEPRIME_DEBT_MS: u32 = GROW_STEP_MS;
+/// How long a failed probe keeps the sync loop from driving another shrink. Without this the
+/// loop pays an audible starvation event every [`SHRINK_QUIET_SYNC_MS`] on any link whose jitter
+/// genuinely needs the depth — sync asks for less, the ring shrinks, the link answers, the ring
+/// grows back, five quiet seconds later sync asks again, forever. Doubles per consecutive
+/// failure up to [`SYNC_BACKOFF_MAX_MS`]; a probe that survives its window resets it.
+const SYNC_BACKOFF_MS: u32 = 60_000;
+const SYNC_BACKOFF_MAX_MS: u32 = 480_000;
 
 /// The playback de-jitter state machine shared by every client's audio ring.
 ///
@@ -539,6 +564,24 @@ pub struct JitterPolicy {
     /// behaviour exactly, which is what lets the four client rings adopt this one at a time
     /// without diverging in the meantime.
     sync_target: Option<usize>,
+    /// Set by [`step`](Self::step) when the read it authorised leaves less than
+    /// [`NEAR_MISS_MARGIN_MS`] buffered; consumed by [`note_read`](Self::note_read).
+    near_miss: bool,
+    /// A near-miss already grew the target this window — one step per window, so a single
+    /// bunching episode (which lands as a RUN of consecutive near-misses while the ring refills)
+    /// buys one measured step, not a sprint to the ceiling.
+    near_miss_grown: bool,
+    /// Set by [`step`](Self::step): the depth average sits more than [`DEPRIME_DEBT_MS`] below
+    /// the target, so an underrun should re-prime at once instead of waiting out the hysteresis.
+    hollow: bool,
+    /// Consumed samples left in the current shrink-probe window (0 = no probe outstanding).
+    probe_run: usize,
+    /// The live target before the probed shrink, restored if the probe fails.
+    probe_prev_target: usize,
+    /// Consumed samples before the sync loop may drive another shrink (0 = allowed now).
+    sync_backoff_run: usize,
+    /// Length of the NEXT backoff, in ms — doubles per consecutive failed probe, capped.
+    sync_backoff_ms: u32,
 }
 
 impl JitterPolicy {
@@ -558,6 +601,13 @@ impl JitterPolicy {
             quiet_run: 0,
             last_want: 0,
             sync_target: None,
+            near_miss: false,
+            near_miss_grown: false,
+            hollow: false,
+            probe_run: 0,
+            probe_prev_target: 0,
+            sync_backoff_run: 0,
+            sync_backoff_ms: SYNC_BACKOFF_MS,
         }
     }
 
@@ -667,8 +717,26 @@ impl JitterPolicy {
         if !self.primed && depth.saturating_sub(out.drop_front) >= target {
             self.primed = true;
             self.empties = 0;
+            // The refill just banked this much: seed the average with it rather than letting it
+            // climb from wherever the drought left it — a freshly-primed ring would otherwise
+            // read as hollow for the EWMA's whole settling time, and the FIRST late packet
+            // would re-prime a ring that is actually full.
+            self.depth_avg = depth.saturating_sub(out.drop_front) as f32;
         }
         out.silence = !self.primed;
+        // Near-miss: this read will be served, but with less than one frame left over — the
+        // next callback starves unless a packet lands within one frame time. Unconditional
+        // assignment, so a stale flag can never survive a de-prime into the next primed read.
+        let after = depth.saturating_sub(out.drop_front);
+        self.near_miss = self.primed
+            && after >= want
+            && after - want < NEAR_MISS_MARGIN_MS as usize * self.per_ms;
+        // Hollow: the depth AVERAGE runs a debt against the target — the promise has been raised
+        // but the depth was never re-banked (see `DEPRIME_DEBT_MS`). Judged on the average, not
+        // this instant: a single late packet empties the ring for a callback without making it
+        // hollow, and must keep the consecutive-empties hysteresis.
+        self.hollow = self.primed
+            && (self.depth_avg as usize + DEPRIME_DEBT_MS as usize * self.per_ms) < target;
         out
     }
 
@@ -683,19 +751,51 @@ impl JitterPolicy {
             return;
         }
         let want = self.last_want.max(1);
+        let near_miss = std::mem::take(&mut self.near_miss);
         self.window_run += want;
         if self.window_run >= GROW_WINDOW_MS as usize * self.per_ms {
             self.window_run = 0;
             self.underruns = 0;
+            self.near_miss_grown = false;
+        }
+        self.sync_backoff_run = self.sync_backoff_run.saturating_sub(want);
+        let mut restored = false;
+        if self.probe_run > 0 {
+            self.probe_run = self.probe_run.saturating_sub(want);
+            if ran_short || near_miss {
+                // The probe FAILED: the link answered a shrink with (nearly) starving the ring.
+                // Take the depth straight back — re-learning it three audible underruns at a
+                // time is what made the sync-vs-growth tug-of-war audible — and keep the sync
+                // loop from probing again for a while, doubling per consecutive failure. The
+                // residual A/V offset is reported instead; continuity outranks sync. The
+                // restore CONSUMES this event as growth evidence: it answered a depth the ring
+                // is no longer at, so growing past the proven target on top would overshoot.
+                self.probe_run = 0;
+                self.target = self.target.max(self.probe_prev_target);
+                self.sync_backoff_run = self.sync_backoff_ms as usize * self.per_ms;
+                self.sync_backoff_ms = (self.sync_backoff_ms * 2).min(SYNC_BACKOFF_MAX_MS);
+                restored = true;
+            } else if self.probe_run == 0 {
+                // Survived the whole window: the shallower depth is genuinely safe here, so the
+                // next probe starts from a clean slate.
+                self.sync_backoff_ms = SYNC_BACKOFF_MS;
+            }
         }
         if ran_short {
             self.quiet_run = 0;
             self.empties += 1;
-            if self.empties >= self.tuning.deprime_after {
+            if self.empties >= self.tuning.deprime_after || self.hollow {
+                // The consecutive-empties hysteresis protects a FULL ring from one late packet.
+                // A hollow ring is the opposite case: the target has been raised but the depth
+                // never re-banked (growth is a promise; only a re-prime cashes it), and riding
+                // that out is a click per bunching period, forever. The click just heard has
+                // already paid for the refill — take it now.
                 self.primed = false;
                 self.empties = 0;
             }
-            self.underruns += 1;
+            if !restored {
+                self.underruns += 1;
+            }
             if self.underruns >= GROW_UNDERRUNS {
                 // This device genuinely needs more slack than the base target. Grow ONCE per
                 // window, capped — the alternative (every device pre-paying the worst device's
@@ -705,17 +805,33 @@ impl JitterPolicy {
                 let grown = self.target + GROW_STEP_MS as usize * self.per_ms;
                 self.target = grown.min(self.tuning.max_target_ms as usize * self.per_ms);
             }
+        } else if near_miss {
+            // Came within one frame of an underrun — the same evidence as one, heard by no one.
+            // Growing here, BEFORE the click, is what "no audible jitter" means: waiting for
+            // the third audible underrun means the user heard two. One step per window (a
+            // bunching episode is a RUN of near-misses while the ring refills, and must buy one
+            // measured step, not a sprint to the ceiling); if it worsens into real underruns
+            // the path above takes over. A near-miss is pressure, not quiet.
+            self.quiet_run = 0;
+            self.empties = 0;
+            if !self.near_miss_grown && !restored {
+                self.near_miss_grown = true;
+                let grown = self.target + GROW_STEP_MS as usize * self.per_ms;
+                self.target = grown.min(self.tuning.max_target_ms as usize * self.per_ms);
+            }
         } else {
             self.empties = 0;
             self.quiet_run += want;
             // A grown target normally relaxes only after a long quiet spell, because without other
             // evidence the only thing that can justify giving up hard-won slack is time. When the
             // sync loop is asking to run shallower it IS that evidence — a measurement saying the
-            // extra depth is costing alignment right now — so test a smaller target sooner. Wrong
-            // guesses are cheap and self-correcting: one underrun and the growth path takes it
-            // straight back. Without this a ring that ratcheted to the ceiling during a transient
-            // would hold the audio a ceiling's worth late for minutes after the cause had gone.
-            let quiet_needed = if self.sync_wants_less() {
+            // extra depth is costing alignment right now — so test a smaller target sooner. Every
+            // shrink is armed as a PROBE: answered by an underrun or near-miss it is undone at
+            // once (see above), and a failed sync-driven guess is not retried for a backoff —
+            // without that, a link whose jitter genuinely needs the depth pays an audible
+            // starvation event every five seconds, forever.
+            let sync_shrink = self.sync_wants_less() && self.sync_backoff_run == 0;
+            let quiet_needed = if sync_shrink {
                 SHRINK_QUIET_SYNC_MS
             } else {
                 SHRINK_QUIET_MS
@@ -725,10 +841,15 @@ impl JitterPolicy {
                 // doesn't cost latency for the rest of the session.
                 self.quiet_run = 0;
                 let base = self.tuning.base_target_ms as usize * self.per_ms;
+                let prev = self.target;
                 self.target = self
                     .target
                     .saturating_sub(GROW_STEP_MS as usize * self.per_ms)
                     .max(base);
+                if self.target < prev {
+                    self.probe_run = SHRINK_PROBE_MS as usize * self.per_ms;
+                    self.probe_prev_target = prev;
+                }
             }
         }
     }
@@ -1937,4 +2058,244 @@ mod tests {
             "sync pressure should relax sooner: {fast_reads} vs {slow_reads} quiet reads"
         );
     }
+
+    // ---- near-miss growth and shrink probes (the audible-limit-cycle fixes) ---------------
+
+    /// A primed read that is served but leaves less than one frame buffered is a NEAR-MISS —
+    /// the same evidence as an underrun, heard by no one — and must grow the target BEFORE the
+    /// click, not after the third one. One step per window: a bunching episode lands as a run of
+    /// consecutive near-misses while the ring refills, and must not sprint to the ceiling.
+    #[test]
+    fn a_near_miss_grows_the_target_without_an_underrun() {
+        let t = JitterTuning::COREAUDIO;
+        let pm = per_ms(2);
+        let want = 5 * pm;
+        let mut p = JitterPolicy::new(t, 2);
+        p.step(t.base_target_ms as usize * pm, want); // primes exactly at target
+        assert!(p.is_primed());
+        let base = p.target_ms();
+        // Serve the callback with less than one frame left over: depth = want + (margin − 1).
+        p.step(want + NEAR_MISS_MARGIN_MS as usize * pm - 1, want);
+        p.note_read(false); // NOT short — the device got its samples
+        assert_eq!(
+            p.target_ms(),
+            base + GROW_STEP_MS,
+            "a near-miss must buy one step"
+        );
+        // A second near-miss in the same window is the same episode: no further growth.
+        p.step(want + pm, want);
+        p.note_read(false);
+        assert_eq!(p.target_ms(), base + GROW_STEP_MS, "one step per window");
+        // A healthy read does not grow anything.
+        let grown = p.target_ms();
+        p.step(grown as usize * pm + want, want);
+        p.note_read(false);
+        assert_eq!(p.target_ms(), grown);
+    }
+
+    /// A healthy steady depth must never read as a near-miss: the margin is one frame, and a
+    /// ring hovering at target sits a whole target above it.
+    #[test]
+    fn steady_depth_never_grows_the_target() {
+        let t = JitterTuning::PIPEWIRE;
+        let pm = per_ms(2);
+        let want = 5 * pm;
+        let mut p = JitterPolicy::new(t, 2);
+        for _ in 0..(60_000 / 5) {
+            // one minute of clean callbacks
+            p.step(t.base_target_ms as usize * pm + want, want);
+            p.note_read(false);
+        }
+        assert_eq!(p.target_ms(), t.base_target_ms);
+    }
+
+    /// A shrink answered by an underrun (or near-miss) inside its probe window is undone AT
+    /// ONCE — re-learning the depth three audible underruns at a time is what made the
+    /// sync-vs-growth tug-of-war audible in the field.
+    #[test]
+    fn a_failed_shrink_probe_is_undone_at_once() {
+        let t = JitterTuning::COREAUDIO;
+        let pm = per_ms(2);
+        let want = 5 * pm;
+        let mut p = JitterPolicy::new(t, 2);
+        // Grow the floor two steps the audible way.
+        for _ in 0..(2 * GROW_UNDERRUNS) {
+            while !p.is_primed() {
+                p.step(200 * pm, want);
+            }
+            p.step(200 * pm, want);
+            p.note_read(true);
+        }
+        let grown = p.target_ms();
+        assert!(grown > t.base_target_ms);
+        // Sync asks for less; five quiet seconds later the shrink probes.
+        p.set_sync_target(Some(pm));
+        let depth = grown as usize * pm + want;
+        while p.target_ms() == grown {
+            p.step(depth, want);
+            p.note_read(false);
+        }
+        assert_eq!(p.target_ms(), grown - GROW_STEP_MS);
+        // ONE near-miss — nobody heard anything yet — and the depth is back.
+        p.step(want + pm, want);
+        p.note_read(false);
+        assert_eq!(
+            p.target_ms(),
+            grown,
+            "a failed probe must restore the target on the first near-miss"
+        );
+    }
+
+    /// After a failed probe the sync loop may not drive another shrink at the accelerated
+    /// cadence — the slow, pre-sync window still applies, the five-second one does not.
+    #[test]
+    fn a_failed_probe_backs_the_sync_shrink_off() {
+        let t = JitterTuning::COREAUDIO;
+        let pm = per_ms(2);
+        let want = 5 * pm;
+        let mut p = JitterPolicy::new(t, 2);
+        for _ in 0..(2 * GROW_UNDERRUNS) {
+            while !p.is_primed() {
+                p.step(200 * pm, want);
+            }
+            p.step(200 * pm, want);
+            p.note_read(true);
+        }
+        let grown = p.target_ms();
+        p.set_sync_target(Some(pm));
+        let depth = grown as usize * pm + want;
+        // First sync-driven shrink, then fail its probe.
+        while p.target_ms() == grown {
+            p.step(depth, want);
+            p.note_read(false);
+        }
+        p.step(want + pm, want);
+        p.note_read(false);
+        assert_eq!(p.target_ms(), grown, "restored");
+        // Twice the accelerated window of clean audio: the backed-off loop must NOT have
+        // shrunk again (before the fix this was exactly one audible failure per five seconds).
+        for _ in 0..(2 * SHRINK_QUIET_SYNC_MS / 5) {
+            p.step(depth, want);
+            p.note_read(false);
+        }
+        assert_eq!(
+            p.target_ms(),
+            grown,
+            "the accelerated cadence must be suspended after a failure"
+        );
+        // The slow pre-sync window still relaxes it eventually — backoff is not a freeze.
+        for _ in 0..(2 * SHRINK_QUIET_MS / 5) {
+            p.step(depth, want);
+            p.note_read(false);
+        }
+        assert!(
+            p.target_ms() < grown,
+            "the slow window must still be allowed to test a shrink"
+        );
+    }
+
+    /// One simulated bunching run's outcome.
+    #[derive(Debug, Default)]
+    struct BunchSim {
+        /// Reads that actually starved the device — each one is audible.
+        audible: u32,
+        /// Audible reads in the second half of the run: non-zero means the policy never
+        /// converged and the user hears it forever.
+        audible_tail: u32,
+    }
+
+    /// Drive a policy over a link that BUNCHES: delivery pauses for `gap_ms` every `period_ms`,
+    /// then the withheld audio arrives at once — the Wi-Fi power-save pattern from the field
+    /// reports, where the total rate is fine and only the spacing is wrong. `drift_ppm` is the
+    /// host-vs-DAC clock skew; a slightly slow host (negative) erodes the depth over minutes,
+    /// which is what keeps re-testing whatever target the policy has settled on — without it a
+    /// simulated ring freezes wherever priming left it and a wrong target is never punished.
+    fn simulate_bunching(
+        tuning: JitterTuning,
+        sync_target: Option<usize>,
+        ms: u32,
+        gap_ms: u32,
+        period_ms: u32,
+        drift_ppm: i64,
+    ) -> BunchSim {
+        let pm = per_ms(2);
+        let want = 5 * pm;
+        let mut p = JitterPolicy::new(tuning, 2);
+        p.set_sync_target(sync_target);
+        let mut depth = 0usize;
+        let mut withheld = 0usize;
+        let mut carry: i64 = 0;
+        let mut out = BunchSim::default();
+        for cb in 0..(ms / 5) {
+            // The host keeps producing (want ± drift per callback); the link decides delivery.
+            carry += want as i64 * drift_ppm;
+            let extra = carry / 1_000_000;
+            carry -= extra * 1_000_000;
+            let produced = (want as i64 + extra).max(0) as usize;
+            let in_gap = (cb * 5) % period_ms < gap_ms;
+            if in_gap {
+                withheld += produced;
+            } else {
+                depth += produced + std::mem::take(&mut withheld);
+            }
+            let s = p.step(depth, want);
+            depth -= s.drop_front.min(depth);
+            if s.silence {
+                p.note_read(false);
+                continue;
+            }
+            let short = depth < want;
+            depth -= want.min(depth);
+            if short {
+                out.audible += 1;
+                if cb >= ms / 10 {
+                    out.audible_tail += 1;
+                }
+            }
+            p.note_read(short);
+        }
+        out
+    }
+
+    /// THE field regression this whole change is for. A link that bunches needs ~30 ms of ring;
+    /// the sync loop wants less. Before this change the policy paid an audible event nearly
+    /// every bunching period, indefinitely — this exact simulation measured ~2000 over ten
+    /// minutes: the sync loop re-probed a proven depth every five quiet seconds, growth needed
+    /// three audible underruns to answer, and a grown target was never re-banked (growth raises
+    /// a threshold; only a re-prime deepens the ring), so the depth rode the knife edge. Now
+    /// near-misses grow the target before the first click, a failed shrink probe is undone at
+    /// once and backs the sync loop off, and a hollow ring cashes the whole refill on the click
+    /// it already paid. What remains is the clock-skew re-anchor — a slightly slow host
+    /// genuinely starves the ring every few minutes, and only rate adaptation (which no client
+    /// has) could remove that — so the bound is "a handful over ten minutes", not zero.
+    #[test]
+    fn sync_pressure_on_a_bunching_link_converges_instead_of_clicking_forever() {
+        // 25 ms gaps every 300 ms, a slightly slow host, ten minutes, sync permanently asking
+        // for a 5 ms ring.
+        let s = simulate_bunching(
+            JitterTuning::COREAUDIO,
+            Some(per_ms(2) * 5),
+            600_000,
+            25,
+            300,
+            -50,
+        );
+        assert!(
+            s.audible_tail <= 4,
+            "the tug-of-war must converge to the skew floor: {s:?}"
+        );
+        assert!(
+            s.audible <= 12,
+            "learning the link may cost a handful of audible events, not a stream of them: {s:?}"
+        );
+    }
+
+    /// The same link without sync pressure — the plain adaptive-growth behaviour — must land in
+    /// the same place: sync steering may not add a persistent audible cost over not steering.
+    #[test]
+    fn a_bunching_link_without_sync_stays_clean_after_growing() {
+        let s = simulate_bunching(JitterTuning::COREAUDIO, None, 600_000, 25, 300, -50);
+        assert!(s.audible_tail <= 4, "{s:?}");
+        assert!(s.audible <= 12, "{s:?}");
+    }
 }

crates/punktfunk-core/src/client/frame_channel.rs

@@ -353,6 +353,18 @@ impl FrameChannel {
     /// all-intra stream ([`Self::set_all_intra`]) a multi-deep queue drains to the NEWEST AU
     /// instead — the skipped ones are already superseded and decode independently, so showing
     /// them only adds latency.
+    ///
+    /// ⚠ **The all-intra drain counts QUEUE ENTRIES and assumes one entry == one AU.** That holds
+    /// today only because slice-progressive delivery is refused on PyroWave
+    /// (`client/pump/handshake.rs`; see [`crate::session::Session::set_deliver_frame_parts`]).
+    /// Turn parts on for an all-intra stream and one AU pushes several entries, at which point
+    /// `len > 1` no longer means "the consumer is behind": this fires mid-AU, hands back a SUFFIX
+    /// and `clear()`s that AU's own prefixes — a headerless frame, every frame. Anyone making the
+    /// two composable must skip whole SUPERSEDED AUs (drop up to the newest entry whose
+    /// `part.first` is set, never split an AU), give `push`'s `FRAME_QUEUE_HARD_CAP` eviction the
+    /// same rule, and count `skipped_total` in AUs. Host-side streamed AUs
+    /// ([`crate::quic::VIDEO_CAP_STREAMED_AU`]) are NOT affected — they still arrive as one
+    /// completed `Frame` per AU.
     pub(crate) fn pop(&self, timeout: Duration) -> FramePop {
         let mut st = self.inner.lock().unwrap();
         if st.q.is_empty() && !st.closed {

crates/punktfunk-core/src/client/pump/handshake.rs

@@ -229,7 +229,10 @@ pub(super) async fn connect_and_handshake(args: &WorkerArgs) -> Result<Handshake
         }
         // Slice-progressive delivery (the embedder's opt-in): AU prefixes hand up as
         // `Frame::part` pieces while the tail is still on the wire. Never on PyroWave — its
-        // all-intra frame channel drains newest-wins, which assumes whole AUs.
+        // all-intra frame channel drains newest-wins per QUEUE ENTRY, so parts of one AU read as
+        // separate AUs and the drain shreds the AU it is mid-way through (`FrameChannel::pop`
+        // spells out the mechanism and what a fix would take). Unrelated to the host's streamed-AU
+        // wire (`VIDEO_CAP_STREAMED_AU`), which still completes one whole `Frame` per AU.
         if args.frame_parts && welcome.codec != crate::quic::CODEC_PYROWAVE {
             session.set_deliver_frame_parts(true);
         }

crates/punktfunk-core/src/quic/endpoint.rs

@@ -82,6 +82,49 @@ fn stream_transport_idle(idle: std::time::Duration) -> Arc<quinn::TransportConfi
     Arc::new(t)
 }
 
+/// Endpoint config for the CLIENT endpoint — the half of the jumbo opt-in that lives on the
+/// receiving side, and without which the whole jumbo leg is unreachable.
+///
+/// `EndpointConfig::max_udp_payload_size` is the QUIC transport parameter this endpoint
+/// advertises: "the largest UDP payload I accept". quinn defaults it to **1472** (a 1500-byte
+/// Ethernet MTU), and a peer's MTU-discovery search is upper-bounded by
+/// `min(MtuDiscoveryConfig::upper_bound, the value the OTHER side advertised)`
+/// (`quinn_proto::connection::mtud::SearchState::new`). So raising the host's probe ceiling
+/// alone — which is all [`stream_transport_idle`] did — can never make a host's discovery
+/// settle above 1472: the *client's* default advertisement caps it, and the host's
+/// settled-at-jumbo proof (`native/wire_mtu.rs`, both the mid-session grow and the
+/// session-start one) could never fire. This raises the advertisement to the sealed jumbo
+/// datagram size so the proof is obtainable at all.
+///
+/// Gated on the SAME operator opt-in as the probe ceiling ([`crate::config::jumbo_wire_mtu`],
+/// i.e. `PUNKTFUNK_JUMBO=1` / `PUNKTFUNK_WIRE_MTU` > 1500) because it is not free: quinn sizes
+/// its endpoint receive buffer as `max_udp_payload_size × max_receive_segments × BATCH_SIZE`,
+/// which on a GRO-capable Linux/Android client is 64 × 32 segments — ~2.9 MiB at the 1472
+/// default, ~18 MiB at jumbo. A jumbo LAN is a deliberate deployment; every other client keeps
+/// today's buffer to the byte. Without the opt-in this returns the stock config, so the
+/// advertisement, the wire, and the memory are all unchanged.
+fn endpoint_config() -> quinn::EndpointConfig {
+    let mut cfg = quinn::EndpointConfig::default();
+    if let Some(mtu) = crate::config::jumbo_wire_mtu() {
+        // Derived exactly like the probe ceiling above (IPv4 overhead — a v6 peer's sealed
+        // target is smaller, so this covers it), and clamped into quinn's accepted range.
+        let shard = crate::config::jumbo_shard_payload_for(
+            mtu,
+            std::net::IpAddr::V4(std::net::Ipv4Addr::UNSPECIFIED),
+        );
+        let accept = crate::config::sealed_datagram_bytes(shard).clamp(1200, 65_527) as u16;
+        if cfg.max_udp_payload_size(accept).is_ok() {
+            tracing::info!(
+                max_udp_payload_size = accept,
+                wire_mtu = mtu,
+                "jumbo opt-in: this endpoint advertises a jumbo QUIC receive ceiling, so the \
+                 peer's MTU discovery can prove a jumbo path (it is capped by this value)"
+            );
+        }
+    }
+    cfg
+}
+
 /// Server endpoint with a fresh self-signed certificate (tests/dev — production hosts
 /// persist an identity and use [`server_with_identity`] so clients can pin it).
 pub fn server(addr: std::net::SocketAddr) -> anyhow_result::Result<quinn::Endpoint> {
@@ -238,7 +281,15 @@ pub fn client_pinned_with_identity(
             .map_err(|e| anyhow_result::Error::msg(format!("quic client config: {e}")))?;
         let mut client_cfg = quinn::ClientConfig::new(Arc::new(quic_cfg));
         client_cfg.transport_config(stream_transport()); // keep-alive — see stream_transport
-        let mut ep = quinn::Endpoint::client("0.0.0.0:0".parse().unwrap())?;
+
+        // `Endpoint::client` hardcodes `EndpointConfig::default()`, whose 1472-byte
+        // `max_udp_payload_size` caps the HOST's MTU discovery (see `endpoint_config`), so the
+        // endpoint is built by hand to carry the jumbo opt-in. Same bind as before
+        // (`0.0.0.0:0`, v4 — no dual-stack flag to reproduce) and the same default runtime.
+        let socket = std::net::UdpSocket::bind("0.0.0.0:0")?;
+        let runtime = quinn::default_runtime()
+            .ok_or_else(|| anyhow_result::Error::msg("no async runtime found".into()))?;
+        let mut ep = quinn::Endpoint::new(endpoint_config(), None, socket, runtime)?;
         ep.set_default_client_config(client_cfg);
         Ok(ep)
     })();
@@ -348,4 +399,80 @@ mod tests {
         let _ = super::stream_transport_idle(std::time::Duration::MAX);
         let _ = super::stream_transport_idle(std::time::Duration::ZERO);
     }
+
+    /// Where a connection's MTU discovery is allowed to climb to, measured rather than argued
+    /// (PW7a). Loopback's own MTU is 64 KiB, so the ONLY thing that can stop the search here is
+    /// configuration — which makes this a clean instrument for the two ceilings:
+    ///
+    /// * **leg A** — server opted in, client NOT: the search stalls at the client's default
+    ///   `max_udp_payload_size` advertisement (1472) no matter how high the server's probe
+    ///   ceiling is. This is why the shipped jumbo grow could never fire: `wire_mtu.rs` waits
+    ///   for a settle at the sealed jumbo size and the peer's transport parameter forbids it.
+    /// * **leg B** — both opted in: the search reaches the sealed jumbo datagram, and the
+    ///   elapsed time is what the `Welcome`'s bounded proof-wait has to cover.
+    ///
+    /// `#[ignore]`d: it sets process-wide env (each endpoint reads the opt-in at construction,
+    /// which is exactly how the two legs are built) and spends seconds of wall clock.
+    /// Run it alone: `cargo test -p punktfunk-core --features quic mtu_discovery -- --ignored
+    /// --nocapture --test-threads=1`.
+    #[tokio::test]
+    #[ignore = "measurement: sets process env and takes ~15 s of wall clock"]
+    async fn mtu_discovery_climbs_only_as_high_as_the_peer_advertises() {
+        async fn climb(server_jumbo: bool, client_jumbo: bool) -> (u16, u128) {
+            let set = |on: bool| {
+                if on {
+                    std::env::set_var("PUNKTFUNK_JUMBO", "1");
+                } else {
+                    std::env::remove_var("PUNKTFUNK_JUMBO");
+                }
+            };
+            set(server_jumbo);
+            let server = endpoint::server("127.0.0.1:0".parse().unwrap()).unwrap();
+            let addr = server.local_addr().unwrap();
+            set(client_jumbo);
+            let client = endpoint::client_insecure().unwrap();
+            set(false);
+            let accept = tokio::spawn(async move {
+                let incoming = server.accept().await.expect("incoming");
+                let conn = incoming.await.expect("host side connects");
+                (server, conn)
+            });
+            let client_conn = client.connect(addr, "punktfunk").unwrap().await.unwrap();
+            let (_server_ep, host_conn) = accept.await.unwrap();
+            // A stream write gives the driver something to transmit, which is what starts the
+            // search (probes ride `poll_transmit`); after that each probe's ack drives the next.
+            let mut s = host_conn.open_uni().await.unwrap();
+            s.write_all(b"go").await.unwrap();
+            let want = crate::config::sealed_datagram_bytes(crate::config::jumbo_shard_payload_for(
+                9000,
+                std::net::IpAddr::V4(std::net::Ipv4Addr::UNSPECIFIED),
+            )) as u16;
+            let t0 = std::time::Instant::now();
+            let mut mtu = host_conn.stats().path.current_mtu;
+            while t0.elapsed() < std::time::Duration::from_secs(6) && mtu < want {
+                tokio::time::sleep(std::time::Duration::from_millis(5)).await;
+                mtu = host_conn.stats().path.current_mtu;
+            }
+            let elapsed = t0.elapsed().as_millis();
+            drop(client_conn);
+            drop(client);
+            (mtu, elapsed)
+        }
+
+        let (capped, _) = climb(true, false).await;
+        println!("leg A (server opted in, client not): settled at {capped} B UDP payload");
+        assert_eq!(
+            capped, 1472,
+            "a peer that advertises the stock max_udp_payload_size caps the search at 1472 — \
+             the whole point of raising it on the client endpoint"
+        );
+
+        let (grown, ms) = climb(true, true).await;
+        println!("leg B (both opted in): reached {grown} B UDP payload in {ms} ms");
+        assert!(
+            grown >= 8972,
+            "both sides opted in, loopback MTU is 64 KiB — discovery should reach the sealed \
+             jumbo datagram, got {grown}"
+        );
+    }
 }

crates/punktfunk-core/src/session.rs

@@ -677,8 +677,21 @@ impl Session {
     /// [`Frame::part`]` = Some` while the rest is still on the wire, instead of one whole-AU
     /// delivery (the slice-progressive decode path — [`crate::packet::USER_FLAG_SLICE_STREAM`]).
     /// With it on, EVERY video frame delivery carries `part: Some` (a frame with no early
-    /// parts arrives as the degenerate `{offset: 0, first, last}` whole). Do not combine with
-    /// an all-intra (PyroWave) stream: its newest-wins draining assumes whole AUs.
+    /// parts arrives as the degenerate `{offset: 0, first, last}` whole).
+    ///
+    /// **Do not combine with an all-intra (PyroWave) stream**, and the reason is sharper than
+    /// "newest-wins draining assumes whole AUs" (2026-08-08, PW6): the drain
+    /// (`client::frame_channel::FrameChannel::pop`) counts QUEUE ENTRIES and takes one entry to be
+    /// one AU. With parts on, a single AU pushes K entries, so `len > 1` stops meaning "the consumer
+    /// is behind" — the drain fires mid-AU, returns the newest entry (a SUFFIX) and clears that
+    /// same AU's prefixes. For PyroWave that is unrecoverable rather than lossy: the sequence
+    /// header lives in window 0 of every AU, so every frame would arrive headerless. Making the
+    /// two composable means teaching the drain to skip whole superseded AUs (never to split one)
+    /// — see the PW6 section of `design/linux-host-performance-wave2-pyrowave.md`.
+    ///
+    /// Note this is a DIFFERENT axis from the host's streamed-AU wire
+    /// ([`crate::quic::VIDEO_CAP_STREAMED_AU`]): a streamed AU still completes as ONE `Frame`
+    /// here, so it is unaffected by any of the above.
     pub fn set_deliver_frame_parts(&mut self, on: bool) {
         self.reassembler.set_deliver_parts(on);
     }

crates/punktfunk-host/src/capture.rs

@@ -194,27 +194,29 @@ pub fn capture_virtual_output(
     crate::inject::set_stream_target(Some(target.target_id));
     let pref = vout.preferred_mode;
     let keep = vout.keepalive;
-    // The sealed-channel delivery seam: resolve the pf-vdisplay control device ONCE (it is
-    // process-global — a dead one is retired, kept alive — so the raw value is stable for the
-    // process) and wrap `send_frame_channel` in a `Send + Sync` closure the IDD-push capturer calls
-    // at ring attach. This is the ONE reach into `crate::vdisplay` the capturer would otherwise make;
-    // building it here keeps the capture→vdisplay dependency out of pf-capture (plan §W6).
+    // The sealed-channel delivery seam: resolve the pf-vdisplay control device ONCE and wrap
+    // `send_frame_channel` in a `Send + Sync` closure the IDD-push capturer calls at ring attach.
+    // This is the ONE reach into `crate::vdisplay` the capturer would otherwise make; building it
+    // here keeps the capture→vdisplay dependency out of pf-capture (plan §W6).
     let control = crate::vdisplay::manager::control_device_handle().ok_or_else(|| {
         anyhow::anyhow!(
             "pf-vdisplay control device not open (monitor not created via the manager?)"
         )
     })?;
-    // `HANDLE` is not `Send`; capture the raw value and rebuild it inside the closure (the control
-    // device is never closed for the process lifetime, so the value stays valid).
-    let control_raw = control.0 as isize;
+    // Each closure keeps its own `Arc<OwnedHandle>` clone (`Send + Sync`), so the handle is open
+    // for exactly as long as any delivery closure lives — and CLOSES once the manager retires it
+    // and the last session drops, which is what lets the wake-from-sleep recovery's PnP device
+    // cycle proceed (an open control handle vetoes it).
+    let control_frame = control.clone();
     let sender: pf_capture::FrameChannelSender = std::sync::Arc::new(
         move |req: &pf_driver_proto::control::SetFrameChannelRequest| {
-            // SAFETY: `control_raw` is the pf-vdisplay control handle resolved above; it is never
-            // closed for the process lifetime, so reconstructing the `HANDLE` and issuing the
-            // `IOCTL_SET_FRAME_CHANNEL` is sound (`send_frame_channel`'s precondition).
+            // SAFETY: the captured `control_frame` Arc keeps the control handle open across this
+            // call — `send_frame_channel`'s precondition.
             unsafe {
                 crate::vdisplay::driver::send_frame_channel(
-                    windows::Win32::Foundation::HANDLE(control_raw as *mut core::ffi::c_void),
+                    windows::Win32::Foundation::HANDLE(
+                        std::os::windows::io::AsRawHandle::as_raw_handle(&*control_frame),
+                    ),
                     req,
                 )
             }
@@ -231,14 +233,17 @@ pub fn capture_virtual_output(
     // Cursor-forward sessions (M2c): hand the capturer the v5 cursor-channel delivery closure —
     // its presence opts the session in (the capturer creates + delivers the CursorShm section,
     // the driver declares the IddCx hardware cursor). Built exactly like `sender` above.
+    let control_cursor = control.clone();
     let cursor_sender: Option<pf_capture::CursorChannelSender> = want.hw_cursor.then(|| {
         std::sync::Arc::new(
             move |req: &pf_driver_proto::control::SetCursorChannelRequest| {
-                // SAFETY: `control_raw` is the pf-vdisplay control handle resolved above; it is
-                // never closed for the process lifetime (`send_cursor_channel`'s precondition).
+                // SAFETY: the captured `control_cursor` Arc keeps the control handle open across
+                // this call (`send_cursor_channel`'s precondition).
                 unsafe {
                     crate::vdisplay::driver::send_cursor_channel(
-                        windows::Win32::Foundation::HANDLE(control_raw as *mut core::ffi::c_void),
+                        windows::Win32::Foundation::HANDLE(
+                            std::os::windows::io::AsRawHandle::as_raw_handle(&*control_cursor),
+                        ),
                         req,
                     )
                 }
@@ -261,11 +266,13 @@ pub fn capture_virtual_output(
                 target_id,
                 enable: enable as u32,
             };
-            // SAFETY: `control_raw` is the pf-vdisplay control handle resolved above; it is
-            // never closed for the process lifetime (`send_cursor_forward`'s precondition).
+            // SAFETY: the captured `control` Arc keeps the control handle open across this call
+            // (`send_cursor_forward`'s precondition).
             unsafe {
                 crate::vdisplay::driver::send_cursor_forward(
-                    windows::Win32::Foundation::HANDLE(control_raw as *mut core::ffi::c_void),
+                    windows::Win32::Foundation::HANDLE(
+                        std::os::windows::io::AsRawHandle::as_raw_handle(&*control),
+                    ),
                     &req,
                 )?;
             }

crates/punktfunk-host/src/library.rs

@@ -29,9 +29,11 @@ mod epic;
 mod gog;
 #[cfg(target_os = "linux")]
 mod heroic;
+mod hidden;
 mod launch;
 #[cfg(target_os = "linux")]
 mod lutris;
+mod plugin_launch;
 mod scanners;
 mod steam;
 #[cfg(windows)]
@@ -46,9 +48,11 @@ pub use epic::*;
 pub use gog::*;
 #[cfg(target_os = "linux")]
 pub use heroic::*;
+pub use hidden::*;
 pub use launch::*;
 #[cfg(target_os = "linux")]
 pub use lutris::*;
+pub use plugin_launch::*;
 pub use scanners::*;
 pub use steam::*;
 #[cfg(windows)]
@@ -195,6 +199,32 @@ pub struct GameEntry {
     pub meta: GameMeta,
 }
 
+/// A library entry plus the operator's own view of it — today, whether they hid it.
+///
+/// A separate type rather than a field on [`GameEntry`] for two reasons. It keeps the visibility
+/// answer out of the providers entirely: a store parser has no opinion on what the operator hid, and
+/// adding `hidden: false` to all eight construction sites would imply it does. More importantly it
+/// makes the lane rule a TYPE guarantee instead of a discipline — `GET /library` answers
+/// `Vec<GameEntry>` on every lane but the operator's, so a hidden entry cannot leak to a paired
+/// client by someone forgetting a filter; there is no field there to leak.
+///
+/// `flatten` keeps the wire shape identical to a plain entry with one extra key, so the console
+/// parses one model either way.
+#[derive(Clone, Debug, Serialize, ToSchema)]
+pub struct OperatorGameEntry {
+    #[serde(flatten)]
+    pub entry: GameEntry,
+    /// The operator hid this title ([`set_entry_hidden`]) — omitted when false, so the shape only
+    /// grows for entries that actually are hidden.
+    #[serde(skip_serializing_if = "is_not_hidden")]
+    pub hidden: bool,
+}
+
+/// `skip_serializing_if` predicate for [`OperatorGameEntry::hidden`] — `&bool` as serde requires.
+fn is_not_hidden(hidden: &bool) -> bool {
+    !*hidden
+}
+
 /// A store that contributes titles to the library. The trait is the extension point for future
 /// launchers; today only [`SteamProvider`] implements it.
 pub trait LibraryProvider {
@@ -268,7 +298,39 @@ impl ArtKind {
 ///   Removing the plugin releases the claim and the built-in comes straight back.
 ///
 /// The user-curated custom store is not a source and always contributes.
+///
+/// A **third** gate rides on top of these two: the operator's per-entry hides (`hidden.rs`). It is
+/// applied here rather than at each call site so a hidden title is gone from every surface by
+/// construction — the grid, native clients, `/applist`, and launch resolution — exactly as a
+/// disabled source's titles are. [`all_games_for_operator`] is the single deliberate exception.
 pub fn all_games() -> Vec<GameEntry> {
+    let hidden = hidden_ids();
+    let mut games = collect_games();
+    games.retain(|g| !hidden.contains(&g.id));
+    games
+}
+
+/// The library **including** the operator's hidden titles, each flagged.
+///
+/// The console's list is the only caller, and only on the operator's own lane (`GET /library`
+/// branches on it): a hidden entry has to be visible SOMEWHERE or it could never be brought back.
+/// Everything else — every paired client, the GameStream app list, launch resolution — goes through
+/// [`all_games`] and never sees them.
+pub fn all_games_for_operator() -> Vec<OperatorGameEntry> {
+    let hidden = hidden_ids();
+    collect_games()
+        .into_iter()
+        .map(|entry| OperatorGameEntry {
+            hidden: hidden.contains(&entry.id),
+            entry,
+        })
+        .collect()
+}
+
+/// Merge every enabled source + the custom entries, sorted by title — with no visibility gate of its
+/// own. Split out so the two public views above cannot drift: they differ only in what they do with
+/// the hidden set, never in what they collect.
+fn collect_games() -> Vec<GameEntry> {
     let off = disabled_scanners();
     let claimed = claimed_stores();
     // A built-in scanner runs when the operator hasn't disabled it AND no plugin has claimed its
@@ -314,3 +376,90 @@ pub fn all_games() -> Vec<GameEntry> {
     games.sort_by_key(|g| g.title.to_lowercase());
     games
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn entry(id: &str, title: &str) -> GameEntry {
+        GameEntry {
+            id: id.into(),
+            store: id.split_once(':').map_or("custom", |(s, _)| s).into(),
+            title: title.into(),
+            art: Artwork::default(),
+            role: GameRole::default(),
+            launch: None,
+            provider: None,
+            detect: DetectSpec::default(),
+            meta: GameMeta::default(),
+        }
+    }
+
+    /// The console codes against this shape, so pin it: the operator view must be a normal entry
+    /// with ONE extra key, and that key must vanish when the title is visible.
+    ///
+    /// The skip matters beyond tidiness — it is what keeps this response byte-identical to the old
+    /// one for a library with nothing hidden, so shipping the feature cannot change what an existing
+    /// console renders until someone actually hides something.
+    #[test]
+    fn operator_entry_flattens_and_omits_hidden_when_false() {
+        let visible = OperatorGameEntry {
+            entry: entry("steam:70", "Half-Life"),
+            hidden: false,
+        };
+        let v = serde_json::to_value(&visible).expect("serializes");
+        assert_eq!(v["id"], "steam:70", "the entry's fields stay at top level");
+        assert_eq!(v["title"], "Half-Life");
+        assert!(
+            v.get("hidden").is_none(),
+            "a visible entry must not carry the key at all: {v}"
+        );
+
+        let hidden = OperatorGameEntry {
+            entry: entry("steam:70", "Half-Life"),
+            hidden: true,
+        };
+        let v = serde_json::to_value(&hidden).expect("serializes");
+        assert_eq!(v["hidden"], true);
+        assert_eq!(v["id"], "steam:70", "flatten still applies when hidden");
+    }
+
+    /// `all_games` and `all_games_for_operator` must agree on WHICH entries exist and differ only in
+    /// visibility — they share `collect_games` for exactly that reason. This pins the shared-source
+    /// property the same way the art test pins write/read symmetry: both views of an id-set built
+    /// from one collector, so a future edit that inlines one of them is caught.
+    #[test]
+    fn hidden_filter_is_the_only_difference_between_the_two_views() {
+        let games = vec![
+            entry("steam:70", "Half-Life"),
+            entry("lutris:4", "Syndicate"),
+            entry("custom:abc", "Chrono Trigger"),
+        ];
+        let hidden: HashSet<String> = ["lutris:4".to_string()].into_iter().collect();
+
+        let operator: Vec<OperatorGameEntry> = games
+            .iter()
+            .cloned()
+            .map(|entry| OperatorGameEntry {
+                hidden: hidden.contains(&entry.id),
+                entry,
+            })
+            .collect();
+        let played: Vec<GameEntry> = games
+            .into_iter()
+            .filter(|g| !hidden.contains(&g.id))
+            .collect();
+
+        assert_eq!(operator.len(), 3, "the operator sees every title");
+        assert_eq!(played.len(), 2, "a player does not see the hidden one");
+        assert!(
+            !played.iter().any(|g| g.id == "lutris:4"),
+            "the hidden id must be absent, not merely flagged"
+        );
+        assert_eq!(
+            operator.iter().filter(|r| r.hidden).count(),
+            1,
+            "exactly the hidden one is flagged"
+        );
+    }
+}

crates/punktfunk-host/src/library/art.rs

@@ -350,8 +350,21 @@ fn sniff_image_type(bytes: &[u8]) -> Option<&'static str> {
 /// write-time half of the art confinement — [`validate_art_paths`] refuses to persist a value this
 /// rejects, so an out-of-root path never reaches the catalog in the first place, and
 /// [`local_art_bytes`] re-checks at read time so an entry written before this existed is still safe.
+///
+/// A `file://` value is decoded to a plain path FIRST, exactly as [`local_art_bytes`] does. Both
+/// halves of the confinement must judge the *same* string or they disagree: `Path::new` on a raw
+/// `file:///home/u/c.jpg` yields a RELATIVE path whose first component is `file:`, which
+/// canonicalizes against the cwd, fails, and reads as "outside every root". That is not a
+/// conservative failure — it rejected every `file://` cover the plugin kit emits (`fileUrl`, the
+/// documented way for a library plugin to publish local art), so the Lutris and Steam scanners
+/// could not reconcile a single entry while the read path would have served those same files
+/// happily.
 pub fn art_path_is_servable(value: &str) -> bool {
-    let p = Path::new(value);
+    // Idempotent for the already-decoded caller: the decoded form no longer carries the prefix,
+    // so `local_art_bytes` passing its own output back through here is a no-op, not a second
+    // percent-decode of a path that legitimately contains `%`.
+    let value = file_url_to_path(value);
+    let p = Path::new(&*value);
     let ext_ok = p
         .extension()
         .and_then(|e| e.to_str())
@@ -699,11 +712,23 @@ mod tests {
 
     const PNG: &[u8] = &[0x89, b'P', b'N', b'G', 0x0D, 0x0A, 0x1A, 0x0A, 0, 0, 0, 13];
 
+    /// `PUNKTFUNK_LIBRARY_ART_ROOTS` is process-global while cargo runs tests as threads, so the
+    /// tests that repoint it must not overlap — one clearing the variable mid-flight makes the
+    /// other's temp root stop being a root, which fails as a confinement bug that isn't there.
+    /// Poisoning is recovered rather than propagated: a panic in one test should report ITS
+    /// failure, not cascade into an unrelated `PoisonError`.
+    static ART_ROOTS_LOCK: std::sync::Mutex<()> = std::sync::Mutex::new(());
+
+    fn lock_art_roots() -> std::sync::MutexGuard<'static, ()> {
+        ART_ROOTS_LOCK.lock().unwrap_or_else(|e| e.into_inner())
+    }
+
     /// The art proxy reads bytes in the HOST process (LocalSystem on Windows) from a path the
     /// plugin lane can write — so what it will and will not read IS the security boundary
     /// (2026-08-05 review H-2). Confinement, extension, and content are all load-bearing.
     #[test]
     fn local_art_bytes_is_confined_and_image_only() {
+        let _guard = lock_art_roots();
         let dir = std::env::temp_dir().join(format!("pf-art-test-{}", std::process::id()));
         let outside = std::env::temp_dir().join(format!("pf-art-out-{}", std::process::id()));
         std::fs::create_dir_all(&dir).unwrap();
@@ -837,6 +862,79 @@ mod tests {
         );
     }
 
+    /// The write gate and the read gate must judge the SAME string.
+    ///
+    /// Regression for 2026-08-08: `validate_art_paths` handed the raw value to `Path::new`, so a
+    /// `file:///…` cover became a *relative* path starting with a `file:` component, canonicalized
+    /// against the cwd, failed, and was refused as "outside every art root" — while
+    /// `local_art_bytes` decoded the very same value and served the file. Every Lutris and Steam
+    /// entry carrying local art was rejected with a 400 the plugin could only report as
+    /// `HostRequestError`, so neither scanner could sync a single game. Asserting servable and
+    /// readable together is the point: either alone passes with the bug present.
+    #[test]
+    fn file_url_art_is_accepted_at_write_time_exactly_as_at_read_time() {
+        let _guard = lock_art_roots();
+        let dir = std::env::temp_dir().join(format!("pf-art-wr-{}", std::process::id()));
+        let outside = std::env::temp_dir().join(format!("pf-art-wr-out-{}", std::process::id()));
+        std::fs::create_dir_all(&dir).unwrap();
+        std::fs::create_dir_all(&outside).unwrap();
+        std::env::set_var("PUNKTFUNK_LIBRARY_ART_ROOTS", &dir);
+
+        let cover = dir.join("cover.png");
+        std::fs::write(&cover, PNG).unwrap();
+
+        // What the kit's `fileUrl` actually emits for a Lutris/Steam cover.
+        let url = file_url(&cover);
+        assert!(
+            is_local_art_path(&url),
+            "a file:// value is local art, so the confinement applies to it"
+        );
+        assert!(
+            art_path_is_servable(&url),
+            "write time must accept the file:// form of a servable cover"
+        );
+        assert!(
+            validate_art_paths(&Artwork {
+                portrait: Some(url.clone()),
+                header: Some(url),
+                ..Default::default()
+            })
+            .is_ok(),
+            "a real Lutris-shaped payload must reconcile"
+        );
+
+        // A percent-encoded name (the reason the decode exists at all) survives the round trip.
+        let spaced = dir.join("My Cover.png");
+        std::fs::write(&spaced, PNG).unwrap();
+        let spaced_url = file_url(&spaced).replace(' ', "%20");
+        assert!(
+            art_path_is_servable(&spaced_url),
+            "percent-encoded names must decode before the containment test: {spaced_url}"
+        );
+        assert!(local_art_bytes(&spaced_url).is_some(), "read time agrees");
+
+        // Loosening the write gate must not loosen the confinement: outside the root is still
+        // refused in file:// clothing, which is what the raw-string bug was accidentally doing.
+        let elsewhere = outside.join("cover.png");
+        std::fs::write(&elsewhere, PNG).unwrap();
+        assert!(
+            !art_path_is_servable(&file_url(&elsewhere)),
+            "file:// must not escape the art roots at write time either"
+        );
+        assert!(
+            validate_art_paths(&Artwork {
+                portrait: Some(file_url(&elsewhere)),
+                ..Default::default()
+            })
+            .is_err(),
+            "an out-of-root file:// cover is still refused"
+        );
+
+        std::env::remove_var("PUNKTFUNK_LIBRARY_ART_ROOTS");
+        let _ = std::fs::remove_dir_all(&dir);
+        let _ = std::fs::remove_dir_all(&outside);
+    }
+
     #[test]
     fn sniff_image_type_recognizes_containers_and_rejects_secrets() {
         assert_eq!(sniff_image_type(PNG), Some("image/png"));

crates/punktfunk-host/src/library/custom.rs

@@ -476,6 +476,15 @@ pub fn validate_provider_payload(inputs: &[ProviderEntryInput]) -> Result<(), St
                     "entries[{i}]: `launch.value` for kind `xbox` must be `<Identity>!<AppId>`"
                 ));
             }
+            // `plugin`: the value is an opaque key in the OWNING plugin's own namespace, handed back
+            // to it at launch time (see `library::ask_plugin_launch`). The host never parses it, so
+            // the only checks are the ones that keep it loggable and bounded.
+            if launch.kind == "plugin" && !valid_plugin_entry_key(&launch.value) {
+                return Err(format!(
+                    "entries[{i}]: `launch.value` for kind `plugin` must be 1–512 chars with no \
+                     control characters"
+                ));
+            }
         }
         if let Some(marker) = &e.detect.env_marker {
             if !valid_env_key(&marker.key) {

crates/punktfunk-host/src/library/hidden.rs

@@ -0,0 +1,141 @@
+//! Per-entry visibility: the operator hides one *title*, where `scanners.rs` hides a whole source.
+//!
+//! **Why this is a side table and not a field on the entry.** Only manual custom entries are stored;
+//! a scanner's and a plugin's titles are regenerated from scratch on every scan and every reconcile.
+//! A `hidden` flag written onto one of those would be erased by the next sync — silently, and
+//! minutes later, which is the worst possible shape for a setting. So the operator's choice lives
+//! here, keyed by the entry's stable `<store>:<external_id>` id, and the entries stay disposable.
+//!
+//! That id is stable *by construction* (design D2): a claimed store's entries keep
+//! `<store>:<external_id>` across reconciles no matter what the host-assigned id does, which is the
+//! same property GameStream app ids and client art caches already depend on. Hiding therefore
+//! survives a re-scan, a plugin restart, and the built-in→plugin migration for a store.
+//!
+//! Hiding is **curation, not access control** — it declutters a grid. It is applied in
+//! [`all_games`](crate::library::all_games), so a hidden title is gone from every play surface
+//! *including* launch resolution (the same reach a disabled scanner has), but nothing is deleted and
+//! un-hiding is immediate. The console is the one surface that still sees hidden titles — otherwise
+//! there would be no way to un-hide one — and only on the operator's own lane.
+
+use super::*;
+
+/// Persisted shape (`library-hidden.json`): the ids the operator hid. Absent file = nothing hidden.
+///
+/// Mirrors `library-scanners.json`'s disabled-set rather than sharing it: that file answers "which
+/// SOURCES run", this one answers "which TITLES show", and a source id (`steam`) and an entry id
+/// (`steam:70`) are different namespaces. Keeping them apart means neither migration can corrupt the
+/// other, and an operator reading either file sees one idea.
+#[derive(Debug, Default, Serialize, Deserialize)]
+struct HiddenSettings {
+    #[serde(default)]
+    hidden: Vec<String>,
+}
+
+fn settings_path() -> PathBuf {
+    // Same hardened config dir as library.json / library-scanners.json.
+    pf_paths::config_dir().join("library-hidden.json")
+}
+
+/// Load the hidden set (default + non-fatal if the file is absent or malformed).
+///
+/// A malformed file means "nothing hidden", never "hide everything": the failure mode of a bad parse
+/// must be a library that shows too much, not one that looks empty and reads as data loss.
+fn load_settings() -> HiddenSettings {
+    match std::fs::read_to_string(settings_path()) {
+        Ok(raw) => serde_json::from_str(&raw).unwrap_or_else(|e| {
+            tracing::warn!(error = %e, "library-hidden.json malformed — nothing hidden");
+            HiddenSettings::default()
+        }),
+        Err(_) => HiddenSettings::default(),
+    }
+}
+
+fn save_settings(settings: &HiddenSettings) -> Result<()> {
+    let dir = pf_paths::config_dir();
+    pf_paths::create_private_dir(&dir).with_context(|| format!("create {}", dir.display()))?;
+    let json = serde_json::to_string_pretty(settings)?;
+    // Write-then-rename like the catalog, so a crash mid-write never truncates the settings.
+    let tmp = settings_path().with_extension("json.tmp");
+    pf_paths::write_secret_file(&tmp, json.as_bytes())
+        .with_context(|| format!("write {}", tmp.display()))?;
+    std::fs::rename(&tmp, settings_path()).context("rename library-hidden.json")?;
+    Ok(())
+}
+
+/// The hidden entry ids, loaded once per library read.
+pub(crate) fn hidden_ids() -> HashSet<String> {
+    load_settings().hidden.into_iter().collect()
+}
+
+/// The store half of a library id (`steam:70` → `steam`), for the `library.changed` source.
+///
+/// Falls back to the whole id rather than an empty string: an id without a `:` is not a shape this
+/// host produces, and naming it in the event beats emitting a blank source that matches no cache key.
+fn store_of(id: &str) -> &str {
+    id.split_once(':').map_or(id, |(store, _)| store)
+}
+
+/// Hide or un-hide one entry. Returns whether the entry is hidden **after** the call.
+///
+/// Idempotent, and deliberately not validated against the current library: an entry can be absent
+/// right now for reasons that have nothing to do with the operator's intent — the launcher is closed,
+/// a plugin has not finished its first sync, a disk is unmounted. Refusing to hide a title that is
+/// temporarily missing, or silently dropping the choice when it comes back, would both be worse than
+/// storing an id that currently matches nothing. Persists and emits `library.changed` only when the
+/// state actually changed, so a repeated PUT is a cheap no-op.
+pub fn set_entry_hidden(id: &str, hidden: bool) -> Result<bool> {
+    let mut settings = load_settings();
+    let was_hidden = settings.hidden.iter().any(|h| h == id);
+    if was_hidden == hidden {
+        return Ok(hidden);
+    }
+    if hidden {
+        settings.hidden.push(id.to_string());
+        settings.hidden.sort();
+        settings.hidden.dedup();
+    } else {
+        settings.hidden.retain(|h| h != id);
+    }
+    save_settings(&settings)?;
+    crate::events::emit(crate::events::EventKind::LibraryChanged {
+        source: store_of(id).to_string(),
+    });
+    Ok(hidden)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// The event source is the STORE, not the whole id — that is the key every client cache and the
+    /// console's query invalidation is grouped by.
+    #[test]
+    fn store_of_takes_the_prefix_and_tolerates_a_bare_id() {
+        assert_eq!(store_of("steam:70"), "steam");
+        assert_eq!(store_of("custom:abc"), "custom");
+        // An external id may itself contain a colon (Heroic's `legendary:<hash>`): split on the
+        // FIRST one, or the store would come back wrong for exactly the store that does this.
+        assert_eq!(store_of("heroic:legendary:fc0b13b7"), "heroic");
+        assert_eq!(store_of("weird-no-colon"), "weird-no-colon");
+    }
+
+    /// A malformed settings file must read as "nothing hidden". The inverse — treating a parse
+    /// failure as "hide everything" — would present as a library that lost its games.
+    #[test]
+    fn malformed_settings_hide_nothing() {
+        let s: HiddenSettings = serde_json::from_str("{ not json").unwrap_or_default();
+        assert!(s.hidden.is_empty());
+        let s: HiddenSettings = serde_json::from_str("{}").expect("an empty object is valid");
+        assert!(s.hidden.is_empty(), "absent key means nothing hidden");
+    }
+
+    /// The persisted shape is the contract an operator may hand-edit — pin it.
+    #[test]
+    fn settings_roundtrip_the_documented_shape() {
+        let s: HiddenSettings =
+            serde_json::from_str(r#"{"hidden":["steam:70","lutris:4"]}"#).expect("parses");
+        assert_eq!(s.hidden, vec!["steam:70", "lutris:4"]);
+        let json = serde_json::to_string(&s).expect("serializes");
+        assert_eq!(json, r#"{"hidden":["steam:70","lutris:4"]}"#);
+    }
+}

crates/punktfunk-host/src/library/launch.rs

@@ -52,7 +52,9 @@ pub fn resolve_launch(id: &str) -> Option<LaunchTarget> {
     {
         // Linux runs the command itself, so a title without one has nothing to launch — same answer
         // (and same warning path) as before this resolution existed.
-        let command = entry.launch.as_ref().and_then(command_for)?;
+        let command = plugin_recipe(&entry)
+            .map(|l| l.command)
+            .or_else(|| entry.launch.as_ref().and_then(command_for))?;
         Some(LaunchTarget {
             game,
             launcher: entry.role == GameRole::Launcher,
@@ -74,9 +76,66 @@ pub fn resolve_launch(id: &str) -> Option<LaunchTarget> {
     }
 }
 
+/// The recipe for a `plugin`-kind entry, asked of the plugin that owns it. `None` for every other
+/// kind (without doing any I/O), so both per-OS resolvers can simply try this first.
+///
+/// This lives beside [`resolve_launch`] / [`launch_title`] rather than inside `command_for` /
+/// `windows_launch_for` because it needs the entry's **`provider`** — and that field is the whole
+/// authorization story. `provider` is stamped by the host from the reconcile URL
+/// (`PUT /library/provider/{provider}`), never taken from the payload, so it is what decides which
+/// plugin gets asked. A plugin that plants an entry under someone else's provider only causes that
+/// *other* plugin to be asked about a key it never published — which is a 404, not a launch.
+///
+/// **Blocking**: see [`ask_plugin_launch`]. `resolve_launch`'s async callers hop through
+/// `spawn_blocking`; the handshake probe uses [`launch_is_resolvable`], which never asks.
+fn plugin_recipe(entry: &GameEntry) -> Option<PluginLaunch> {
+    let spec = entry.launch.as_ref()?;
+    if spec.kind != "plugin" {
+        return None;
+    }
+    let Some(provider) = entry.provider.as_deref() else {
+        // Only a provider reconcile can author this kind, so this is unreachable short of a
+        // hand-edited library.json — say so rather than silently doing nothing.
+        tracing::warn!(
+            id = %entry.id,
+            "plugin launch: entry carries no provider, so no plugin can answer for it"
+        );
+        return None;
+    };
+    ask_plugin_launch(provider, &spec.value)
+}
+
+/// Whether `id` will actually launch something — **without asking a plugin**.
+///
+/// The handshake needs this one bit to decide dedicated-session routing, and it runs on the async
+/// path, so it must not make a blocking call out to a plugin. For a `plugin`-kind entry the cheap
+/// answer is "a live plugin is registered under its provider, and the key is well formed"; if that
+/// plugin later refuses the ask, the launch fails the same way any unresolvable entry does and the
+/// player is left on the session.
+#[cfg(not(windows))]
+pub fn launch_is_resolvable(id: &str) -> bool {
+    let Some(entry) = all_games().into_iter().find(|g| g.id == id) else {
+        return false;
+    };
+    let Some(spec) = entry.launch.as_ref() else {
+        return false;
+    };
+    if spec.kind == "plugin" {
+        return valid_plugin_entry_key(&spec.value)
+            && entry
+                .provider
+                .as_deref()
+                .is_some_and(|p| crate::mgmt::ui_credential(p).is_some());
+    }
+    command_for(spec).is_some()
+}
+
 /// Map a resolved [`LaunchSpec`] to its shell command (pure — the unit-testable core of
 /// [`resolve_launch`], split out so the appid-validation can be tested without a Steam install).
 ///
+/// The `plugin` kind is deliberately absent: its answer comes from another process, so it is
+/// resolved by [`plugin_recipe`] before this is reached.
+///
 /// - `steam_appid` → `steam steam://rungameid/<appid>` (appid validated as digits).
 /// - `command` → the stored command verbatim. This string comes from the host's own custom store
 ///   (added by the host operator via the admin UI), never from the client, so it is trusted.
@@ -126,17 +185,24 @@ fn command_for(spec: &LaunchSpec) -> Option<String> {
 /// desktop and grabs foreground.
 #[cfg(windows)]
 pub fn launch_title(id: &str) -> Result<()> {
-    let spec = all_games()
+    let entry = all_games()
         .into_iter()
         .find(|g| g.id == id)
-        .and_then(|g| g.launch)
+        .filter(|g| g.launch.is_some())
         .ok_or_else(|| anyhow::anyhow!("no launchable library entry '{id}'"))?;
-    let (cmdline, workdir) = windows_launch_for(&spec).ok_or_else(|| {
-        anyhow::anyhow!(
-            "library entry '{id}' has no Windows launch recipe (kind '{}')",
-            spec.kind
-        )
-    })?;
+    let spec = entry.launch.clone().expect("filtered to Some above");
+    // A `plugin` entry's recipe comes from the plugin that owns it, and arrives in the same
+    // (command line, working dir) shape this path already spawns. `windows_launch_for` has no arm
+    // for the kind, so a failed ask falls through to the "no recipe" error below.
+    let (cmdline, workdir) = plugin_recipe(&entry)
+        .map(|l| (l.command, l.cwd))
+        .or_else(|| windows_launch_for(&spec))
+        .ok_or_else(|| {
+            anyhow::anyhow!(
+                "library entry '{id}' has no Windows launch recipe (kind '{}')",
+                spec.kind
+            )
+        })?;
     let pid = crate::interactive::spawn_in_active_session(&cmdline, workdir.as_deref())
         .with_context(|| format!("launch '{id}' in the interactive session"))?;
     tracing::info!(launch_id = id, %cmdline, pid, "launched library title in the interactive session");
@@ -148,6 +214,9 @@ pub fn launch_title(id: &str) -> Result<()> {
 ///
 /// CreateProcessAsUserW does NO shell or protocol resolution, so the URI/flags are handed to a
 /// concrete EXE as plain arguments — a (host-derived) URI string can never reach a command interpreter.
+///
+/// The `plugin` kind is deliberately absent: its answer comes from another process, so it is
+/// resolved by [`plugin_recipe`] before this is reached.
 #[cfg(windows)]
 fn windows_launch_for(spec: &LaunchSpec) -> Option<(String, Option<std::path::PathBuf>)> {
     match spec.kind.as_str() {

crates/punktfunk-host/src/library/plugin_launch.rs

@@ -0,0 +1,364 @@
+//! The `plugin` launch kind's transport: ask a library plugin what to run for one of **its own**
+//! entries, at launch time, over the loopback UI surface it already registered.
+//!
+//! ## Why the host asks instead of storing a command
+//!
+//! A ROM tile is `<emulator> <args> <rom>` — an operator-configured command line, and the one shape
+//! [`super::privileged_field`] refuses from the plugin lane (2026-08-05 review H-1). The Playnite
+//! plugin hit the same wall and was rescued with a typed `playnite` kind the host resolves itself
+//! (see `command_for`), but that only works because a Playnite launch is a fixed URI scheme. There
+//! is no fixed scheme for "some emulator the operator installed, with the core and flags they chose"
+//! — the knowledge lives in the plugin, and it is the plugin that owns the hardened quoting seam for
+//! it (ROM filenames are untrusted input).
+//!
+//! So the entry carries an **opaque key** and nothing executable, and the command is fetched from
+//! the owning plugin at the moment of an actual launch. What that buys over letting the plugin write
+//! `kind = "command"` straight into the library:
+//!
+//! * **A stolen plugin token is no longer command execution.** Planting an entry is not enough — the
+//!   host asks the *live registered plugin* what to run, authenticated with the per-boot secret only
+//!   that process knows. A plugin asked about an entry it never published answers 404 (this is why
+//!   the ask names the entry rather than trusting the payload), so a forged entry launches nothing.
+//! * **Nothing executable is ever persisted or served.** No command lands in `library.json`, and
+//!   `GET /library` has none to redact for a paired client.
+//! * **No stale recipes.** The same reasoning as the `xbox` kind resolving its AUMID at launch time:
+//!   an emulator that moved, or a config the operator has since edited, is picked up on the next
+//!   launch instead of leaving an unlaunchable tile behind.
+//!
+//! The host still *runs* the command, because only the host can put the process where the stream can
+//! see it: on Linux the line is either gamescope's own argv (a bare-spawn session nests it) or a
+//! spawn carrying the session's compositor env, and the returned child is what
+//! `design/session-game-lifetime.md` tracks to know the game exited. A plugin spawning the emulator
+//! itself would land it outside the captured session and outside that lifetime.
+
+use super::*;
+use std::io::Read;
+use std::time::Duration;
+
+/// The whole ask, end to end. A plugin resolving one of its own entries is a local lookup against
+/// state it already holds, so this is generous for a healthy plugin and short enough that a wedged
+/// one cannot hold a launch — or, on the GameStream plane, the data-plane thread that calls this —
+/// for longer than a player would keep staring at a tile that did nothing.
+const ASK_TIMEOUT: Duration = Duration::from_secs(3);
+
+/// A command LINE, not a script. Generous for `flatpak run … --core=… "/very/long/rom path"`,
+/// bounded so a malformed answer cannot land a megabyte in the logs or in a shell argument.
+const MAX_COMMAND: usize = 4096;
+
+/// Cap the whole response body — the shape is two short strings.
+const MAX_BODY: usize = 64 * 1024;
+
+/// What a plugin answered: the command line to run, and optionally the directory to run it in
+/// (emulators that resolve cores or configs relative to their install dir need one).
+pub struct PluginLaunch {
+    pub command: String,
+    pub cwd: Option<PathBuf>,
+}
+
+/// The wire shape of `POST /__launch`'s response.
+#[derive(Deserialize)]
+struct LaunchReply {
+    command: String,
+    #[serde(default)]
+    cwd: Option<String>,
+}
+
+/// The opaque per-entry key a `plugin` launch carries. It is echoed to the owning plugin as JSON and
+/// lands in log lines, so bound it and keep control characters out; everything else is the plugin's
+/// own namespace (rom-manager uses its `<platform>/<relpath>` external id).
+pub fn valid_plugin_entry_key(v: &str) -> bool {
+    !v.is_empty() && v.len() <= 512 && !v.chars().any(char::is_control)
+}
+
+/// Ask `plugin` what to run for its entry `key`.
+///
+/// `None` — the plugin is not registered/live, has no UI surface, disowns the entry, or answered
+/// something unusable. Every arm logs, because from a player's seat all of them look like "the tile
+/// did nothing", and the difference is exactly what an operator needs to fix it.
+///
+/// **Blocking** (`ureq`, the host's existing off-runtime HTTP client): callers run on a blocking
+/// thread. `resolve_launch`'s async callers hop through `spawn_blocking`, and the handshake's
+/// "is this launchable at all" probe uses [`super::launch_is_resolvable`], which never asks.
+pub fn ask_plugin_launch(plugin: &str, key: &str) -> Option<PluginLaunch> {
+    if !valid_plugin_entry_key(key) {
+        tracing::warn!(
+            plugin,
+            "plugin launch: entry key failed validation — ignoring"
+        );
+        return None;
+    }
+    let Some(cred) = crate::mgmt::ui_credential(plugin) else {
+        tracing::warn!(
+            plugin,
+            entry = key,
+            "plugin launch: no live plugin registered under that provider id (is it running?) — \
+             nothing to launch"
+        );
+        return None;
+    };
+    let agent = ureq::AgentBuilder::new().timeout(ASK_TIMEOUT).build();
+    // Loopback + the plugin's own per-boot secret, exactly what the console proxy presents. The
+    // registration stores a PORT, never an address (mgmt::plugins D5), so this can only ever dial
+    // this machine.
+    // `send_string` + an explicit content type rather than `send_json`: that one needs ureq's `json`
+    // feature, and the body is one field.
+    let body = serde_json::json!({ "entry": key }).to_string();
+    let resp = match agent
+        .post(&format!("http://127.0.0.1:{}/__launch", cred.port))
+        .set("Authorization", &format!("Bearer {}", cred.secret))
+        .set("Content-Type", "application/json")
+        .send_string(&body)
+    {
+        Ok(r) => r,
+        // A plugin that does not know the entry says so with a 404 — the answer a FORGED entry gets,
+        // and the reason planting one is not enough to make the host run anything.
+        Err(ureq::Error::Status(404, _)) => {
+            tracing::warn!(
+                plugin,
+                entry = key,
+                "plugin launch: the plugin does not own an entry with that key — nothing to launch"
+            );
+            return None;
+        }
+        Err(ureq::Error::Status(code, _)) => {
+            tracing::warn!(
+                plugin,
+                entry = key,
+                code,
+                "plugin launch: the plugin refused to resolve the entry"
+            );
+            return None;
+        }
+        Err(e) => {
+            tracing::warn!(
+                plugin,
+                entry = key,
+                error = %e,
+                "plugin launch: could not reach the plugin's launch surface"
+            );
+            return None;
+        }
+    };
+    let mut buf = Vec::new();
+    if let Err(e) = resp
+        .into_reader()
+        .take((MAX_BODY + 1) as u64)
+        .read_to_end(&mut buf)
+    {
+        tracing::warn!(plugin, entry = key, error = %e, "plugin launch: reading the answer failed");
+        return None;
+    }
+    if buf.len() > MAX_BODY {
+        tracing::warn!(
+            plugin,
+            entry = key,
+            "plugin launch: answer exceeds the {MAX_BODY}-byte cap"
+        );
+        return None;
+    }
+    let reply: LaunchReply = match serde_json::from_slice(&buf) {
+        Ok(r) => r,
+        Err(e) => {
+            tracing::warn!(plugin, entry = key, error = %e, "plugin launch: answer was not {{command, cwd}}");
+            return None;
+        }
+    };
+    validate_reply(plugin, key, reply)
+}
+
+/// The checks on what came back, split out so they can be tested without a plugin on a port.
+fn validate_reply(plugin: &str, key: &str, reply: LaunchReply) -> Option<PluginLaunch> {
+    let command = reply.command.trim().to_string();
+    if command.is_empty() {
+        tracing::warn!(
+            plugin,
+            entry = key,
+            "plugin launch: answered an empty command"
+        );
+        return None;
+    }
+    if command.len() > MAX_COMMAND {
+        tracing::warn!(
+            plugin,
+            entry = key,
+            "plugin launch: command exceeds the {MAX_COMMAND}-byte cap"
+        );
+        return None;
+    }
+    // Hygiene rather than a security boundary — a plugin that wanted two commands could always write
+    // `a; b`, and composing the line is its job. But a launch command is ONE line: keeping control
+    // characters out is what makes the logged line the line that ran, and what stops a stray `\r`
+    // from mangling the Windows `cmd.exe /c` form.
+    if command.chars().any(char::is_control) {
+        tracing::warn!(
+            plugin,
+            entry = key,
+            "plugin launch: command contains control characters — refusing it"
+        );
+        return None;
+    }
+    let cwd = match reply
+        .cwd
+        .as_deref()
+        .map(str::trim)
+        .filter(|c| !c.is_empty())
+    {
+        None => None,
+        Some(dir) => {
+            let path = PathBuf::from(dir);
+            // Relative to WHAT? The host's cwd is not the plugin's, and a launch that silently ran
+            // somewhere unintended is worse than one that says why it did not.
+            if !path.is_absolute() {
+                tracing::warn!(
+                    plugin,
+                    entry = key,
+                    cwd = dir,
+                    "plugin launch: working directory must be absolute — refusing it"
+                );
+                return None;
+            }
+            Some(path)
+        }
+    };
+    Some(PluginLaunch { command, cwd })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::io::Write;
+
+    /// A one-shot HTTP/1.1 stub on an ephemeral loopback port. Returns the port and a handle that
+    /// yields the raw request text — so the assertions about what the HOST sent (method, path,
+    /// bearer, body) live in the test thread, where a failure reads as a failure.
+    fn stub_plugin(status: u16, body: &'static str) -> (u16, std::thread::JoinHandle<String>) {
+        let listener = std::net::TcpListener::bind("127.0.0.1:0").expect("bind loopback");
+        let port = listener.local_addr().expect("local addr").port();
+        let handle = std::thread::spawn(move || {
+            let (mut sock, _) = listener.accept().expect("accept");
+            let mut buf = Vec::new();
+            let mut chunk = [0u8; 1024];
+            // Read until the body named by Content-Length has arrived (ureq always sends one here).
+            loop {
+                let n = sock.read(&mut chunk).expect("read request");
+                if n == 0 {
+                    break;
+                }
+                buf.extend_from_slice(&chunk[..n]);
+                let text = String::from_utf8_lossy(&buf).to_string();
+                if let Some(end) = text.find("\r\n\r\n") {
+                    let len = text[..end]
+                        .lines()
+                        .find_map(|l| {
+                            let (k, v) = l.split_once(':')?;
+                            k.eq_ignore_ascii_case("content-length")
+                                .then(|| v.trim().parse::<usize>().ok())?
+                        })
+                        .unwrap_or(0);
+                    if buf.len() >= end + 4 + len {
+                        break;
+                    }
+                }
+            }
+            let resp = format!(
+                "HTTP/1.1 {status} STATUS\r\nContent-Type: application/json\r\n\
+                 Content-Length: {}\r\nConnection: close\r\n\r\n{body}",
+                body.len()
+            );
+            sock.write_all(resp.as_bytes()).expect("write response");
+            let _ = sock.flush();
+            String::from_utf8_lossy(&buf).to_string()
+        });
+        (port, handle)
+    }
+
+    #[test]
+    fn asks_the_registered_plugin_and_takes_its_answer() {
+        let (port, server) =
+            stub_plugin(200, r#"{"command":"retroarch 'smw.sfc'","cwd":"/opt/emu"}"#);
+        crate::mgmt::register_ui_for_test("stub-launcher", port, "s3cr3t");
+
+        let got = ask_plugin_launch("stub-launcher", "snes/smw.sfc").expect("a recipe");
+        assert_eq!(got.command, "retroarch 'smw.sfc'");
+        assert_eq!(got.cwd.as_deref(), Some(std::path::Path::new("/opt/emu")));
+
+        let req = server.join().expect("stub thread");
+        assert!(req.starts_with("POST /__launch "), "request was {req:?}");
+        // The plugin's own per-boot secret, the same credential the console proxy presents.
+        assert!(
+            req.contains("Bearer s3cr3t"),
+            "the ask must authenticate: {req:?}"
+        );
+        // The entry key is what the plugin resolves against its own state — it must be on the wire.
+        assert!(
+            req.contains(r#""entry":"snes/smw.sfc""#),
+            "body was {req:?}"
+        );
+    }
+
+    #[test]
+    fn a_404_means_the_plugin_disowns_the_entry() {
+        // The forged-entry case: planting a library row is not enough, because the plugin that would
+        // have to answer for it never published one.
+        let (port, server) = stub_plugin(404, r#"{"error":"no launchable entry \"forged\""}"#);
+        crate::mgmt::register_ui_for_test("stub-disowner", port, "s");
+
+        assert!(ask_plugin_launch("stub-disowner", "forged").is_none());
+        server.join().expect("stub thread");
+    }
+
+    #[test]
+    fn an_unregistered_provider_resolves_to_nothing() {
+        // No live plugin, no port to dial, no launch — and no panic.
+        assert!(ask_plugin_launch("no-such-plugin-is-registered", "k").is_none());
+    }
+
+    fn reply(command: &str, cwd: Option<&str>) -> LaunchReply {
+        LaunchReply {
+            command: command.into(),
+            cwd: cwd.map(str::to_string),
+        }
+    }
+
+    #[test]
+    fn entry_keys_are_bounded_and_printable() {
+        assert!(valid_plugin_entry_key("snes/Super Mario World.sfc"));
+        assert!(!valid_plugin_entry_key(""));
+        assert!(!valid_plugin_entry_key("with\nnewline"));
+        assert!(!valid_plugin_entry_key("with\0nul"));
+        assert!(!valid_plugin_entry_key(&"x".repeat(513)));
+    }
+
+    #[test]
+    fn a_usable_answer_passes_through_trimmed() {
+        let got = validate_reply(
+            "rom-manager",
+            "snes/smw",
+            reply("  retroarch 'smw.sfc' \n", None),
+        )
+        .expect("usable");
+        assert_eq!(got.command, "retroarch 'smw.sfc'");
+        assert!(got.cwd.is_none());
+    }
+
+    #[test]
+    fn empty_and_oversized_and_control_char_commands_are_refused() {
+        assert!(validate_reply("p", "k", reply("   ", None)).is_none());
+        assert!(validate_reply("p", "k", reply(&"x".repeat(MAX_COMMAND + 1), None)).is_none());
+        // The interesting one: a second line smuggled into what the host logs as a single command.
+        assert!(validate_reply("p", "k", reply("retroarch rom\nrm -rf ~", None)).is_none());
+    }
+
+    #[test]
+    fn a_working_directory_must_be_absolute() {
+        let abs = if cfg!(windows) { r"C:\emu" } else { "/opt/emu" };
+        let got = validate_reply("p", "k", reply("run", Some(abs))).expect("absolute cwd is fine");
+        assert_eq!(got.cwd.as_deref(), Some(std::path::Path::new(abs)));
+        assert!(validate_reply("p", "k", reply("run", Some("emu/cores"))).is_none());
+        // An empty/whitespace cwd is "no preference", not a refusal.
+        assert!(validate_reply("p", "k", reply("run", Some("  ")))
+            .expect("blank cwd is tolerated")
+            .cwd
+            .is_none());
+    }
+}

crates/punktfunk-host/src/main.rs

@@ -844,6 +844,7 @@ fn parse_spike(args: &[String]) -> Result<Options> {
     let mut bitrate_mbps = 20u64;
     let mut out: Option<PathBuf> = None;
     let mut loopback = true;
+    let mut wire_chunk: Option<usize> = None;
 
     let mut i = 0;
     while i < args.len() {
@@ -890,7 +891,13 @@ fn parse_spike(args: &[String]) -> Result<Options> {
                     "h264" => Codec::H264,
                     "h265" | "hevc" => Codec::H265,
                     "av1" => Codec::Av1,
-                    other => bail!("unknown --codec '{other}' (h264|h265|av1)"),
+                    // The spike is the only way to drive a PyroWave capture→encode pass without
+                    // a client, which is what the Linux-host PyroWave work measures against.
+                    // Needs the `pyrowave` feature (default-on) and pairs with
+                    // `PUNKTFUNK_ENCODER=pyrowave`, which is what puts the CAPTURE side on the
+                    // raw-dmabuf passthrough.
+                    "pyrowave" => Codec::PyroWave,
+                    other => bail!("unknown --codec '{other}' (h264|h265|av1|pyrowave)"),
                 }
             }
             "--bitrate" => {
@@ -900,6 +907,12 @@ fn parse_spike(args: &[String]) -> Result<Options> {
             }
             "--out" => out = Some(PathBuf::from(next()?)),
             "--no-loopback" => loopback = false,
+            "--wire-chunk" => {
+                let v: usize = next()?
+                    .parse()
+                    .map_err(|_| anyhow::anyhow!("bad --wire-chunk (bytes)"))?;
+                wire_chunk = (v > 0).then_some(v);
+            }
             "-h" | "--help" => {
                 print_usage();
                 std::process::exit(0);
@@ -934,6 +947,7 @@ fn parse_spike(args: &[String]) -> Result<Options> {
         bitrate_bps: bitrate_mbps.saturating_mul(1_000_000),
         out,
         loopback,
+        wire_chunk,
     })
 }
 
@@ -1007,11 +1021,18 @@ SPIKE OPTIONS:
                                  KWin virtual output at --width x --height and captures it
     --seconds <N>                capture duration in seconds (default: 5)
     --fps <N>                    target frame rate (default: 60)
-    --codec <h264|h265|av1>      NVENC codec (default: h265)
+    --codec <h264|h265|av1|pyrowave>
+                                 encode codec (default: h265). 'pyrowave' also wants
+                                 PUNKTFUNK_ENCODER=pyrowave so capture takes the passthrough
     --bitrate <MBPS>             target bitrate in Mbps (default: 20)
     --width <W> --height <H>     synthetic source size (default: 1920x1080)
     --out <PATH>                 raw Annex-B output (default: /tmp/punktfunk-spike.<ext>)
     --no-loopback                skip the punktfunk_core round-trip verification
+    --wire-chunk <BYTES>         PyroWave datagram-aligned packetization at this shard payload
+                                 (a real session passes its negotiated shard_payload, e.g. 1408).
+                                 With PUNKTFUNK_PYROWAVE_STREAMED_AU=1 also armed, the AU is
+                                 drained through poll_chunk and sealed as a STREAMED wire frame
+                                 (VIDEO_CAP_STREAMED_AU), then byte-verified by the loopback
     -h, --help                   this help
 
 NOTES:

crates/punktfunk-host/src/mgmt.rs

@@ -47,6 +47,14 @@ mod store;
 mod tests;
 mod update;
 
+/// Lets `library::plugin_launch`'s tests put a stub plugin in the registry (test-only).
+#[cfg(test)]
+pub(crate) use plugins::register_ui_for_test;
+/// The launch path asks a library plugin what to run for its own entries, and needs the loopback
+/// credential this process already holds for it. Re-exported (rather than opening the whole
+/// `plugins` module crate-wide) so these two are the ONLY things `mgmt` lends to the library side.
+pub(crate) use plugins::ui_credential;
+
 /// Default management port — adjacent to the GameStream block (47984…48010), and the same
 /// number Sunshine users already associate with "the config UI".
 pub const DEFAULT_PORT: u16 = 47990;
@@ -228,6 +236,7 @@ fn api_router_parts() -> (Router<Arc<MgmtState>>, utoipa::openapi::OpenApi) {
                 .routes(routes!(library::get_library))
                 .routes(routes!(library::list_library_scanners))
                 .routes(routes!(library::set_library_scanner))
+                .routes(routes!(library::set_library_entry_hidden))
                 .routes(routes!(library::create_custom_game))
                 .routes(routes!(
                     library::update_custom_game,

crates/punktfunk-host/src/mgmt/auth.rs

@@ -51,6 +51,18 @@ impl AuthLane {
     pub(crate) fn may_set_privileged_fields(self) -> bool {
         matches!(self, AuthLane::Admin)
     }
+
+    /// Whether this is the operator's own lane — the console, as opposed to a paired client or a
+    /// plugin.
+    ///
+    /// Same arm as [`may_set_privileged_fields`](Self::may_set_privileged_fields) today, and
+    /// deliberately a separate question: that one asks "may this caller cause command execution",
+    /// this one asks "is this caller the person curating the library". A read-only view the operator
+    /// alone should see (their hidden titles) is not a privilege escalation, and collapsing the two
+    /// would leave whichever one changes first silently answering for the other.
+    pub(crate) fn is_operator(self) -> bool {
+        matches!(self, AuthLane::Admin)
+    }
 }
 
 /// Auth gate on the `/api/v1` routes: a paired client cert (mTLS, from anywhere) or the bearer token

crates/punktfunk-host/src/mgmt/library.rs

@@ -14,33 +14,42 @@ use axum::Extension;
 /// scanner plugin — while `prep` / `launch.kind = "command"` inside that payload are the operator's
 /// authority alone. Route reachability and field authority are separate questions.
 ///
-/// `Some(response)` is the refusal to return; `None` means the payload may proceed. Deliberately
-/// not `Result<(), Response>`: the "error" here IS the response the handler sends, so there is no
-/// error value to propagate, and a 128-byte `Response` in an `Err` variant is what
+/// `Some((reason, response))` is the refusal to return; `None` means the payload may proceed.
+/// Deliberately not `Result<(), Response>`: the "error" here IS the response the handler sends, so
+/// there is no error value to propagate, and a 128-byte `Response` in an `Err` variant is what
 /// `clippy::result_large_err` objects to.
+///
+/// `reason` is the caller's log line. It exists because these are TWO different refusals — an
+/// operator-privileged field (403) and an unservable art path (400) — and logging both as "carries
+/// a field this lane may not set" sent the Lutris/Steam `file://` art rejection looking like an
+/// auth problem. The plugin only ever sees `HostRequestError`, so this log line is the sole
+/// diagnosis surface for whoever has to explain why a scanner syncs nothing.
 fn check_entry_fields(
     lane: AuthLane,
     art: &crate::library::Artwork,
     launch: Option<&crate::library::LaunchSpec>,
     prep: &[crate::hooks::PrepCmd],
-) -> Option<Response> {
+) -> Option<(String, Response)> {
     if !lane.may_set_privileged_fields() {
         if let Some(field) = crate::library::privileged_field(launch, prep) {
-            return Some(api_error(
-                StatusCode::FORBIDDEN,
-                &format!(
-                    "`{field}` is executed as the host user and may only be set with the \
-                     operator's admin token — a plugin may publish entries with any host-resolved \
-                     launch kind (steam_appid, steam_ui, launcher_ui, epic, gog, aumid, xbox, lutris_id, \
-                     heroic, playnite) \
-                     instead"
+            return Some((
+                format!("payload carries `{field}`, which this lane may not set"),
+                api_error(
+                    StatusCode::FORBIDDEN,
+                    &format!(
+                        "`{field}` is executed as the host user and may only be set with the \
+                         operator's admin token — a plugin may publish entries with any host-resolved \
+                         launch kind (steam_appid, steam_ui, launcher_ui, epic, gog, aumid, xbox, lutris_id, \
+                         heroic, playnite) \
+                         instead"
+                    ),
                 ),
             ));
         }
     }
     crate::library::validate_art_paths(art)
         .err()
-        .map(|e| api_error(StatusCode::BAD_REQUEST, &e))
+        .map(|e| (e.clone(), api_error(StatusCode::BAD_REQUEST, &e)))
 }
 
 #[derive(Deserialize)]
@@ -58,6 +67,10 @@ pub(crate) struct LibraryQuery {
 /// fetches directly (the public Steam CDN for Steam titles). `?provider=` narrows to the
 /// entries a given external provider owns; `?platform=` to one platform (case-insensitive —
 /// installed-store titles are `PC`, custom/provider entries carry whatever was authored).
+///
+/// **The operator's own lane additionally sees the titles they have HIDDEN**, each carrying
+/// `hidden: true`; every other lane gets them filtered out upstream and cannot tell they exist. The
+/// console needs them to offer "un-hide", and it is the only surface that does.
 #[utoipa::path(
     get,
     path = "/library",
@@ -68,26 +81,28 @@ pub(crate) struct LibraryQuery {
         ("platform" = Option<String>, Query, description = "Only entries on this platform (case-insensitive, e.g. `PS2`)"),
     ),
     responses(
-        (status = OK, description = "Unified library across all stores", body = [crate::library::GameEntry]),
+        (status = OK, description = "Unified library across all stores (the operator's lane also gets hidden entries, flagged)", body = [crate::library::OperatorGameEntry]),
         (status = UNAUTHORIZED, description = "Missing or invalid bearer token", body = ApiError),
     )
 )]
 pub(crate) async fn get_library(
     Extension(lane): Extension<AuthLane>,
     Query(q): Query<LibraryQuery>,
-) -> Json<Vec<crate::library::GameEntry>> {
+) -> Response {
+    // The operator's list is a DIFFERENT TYPE, not the same one with a flag set — which is what
+    // makes "a hidden title never reaches a paired client" structural rather than a filter someone
+    // has to remember. The redaction below is skipped here because this arm is the operator's own
+    // token: the command line being redacted is the one they typed.
+    if lane.is_operator() {
+        let mut rows = crate::library::all_games_for_operator();
+        rows.retain(|r| matches_query(&r.entry, &q));
+        for r in &mut rows {
+            crate::library::proxy_local_art(&r.entry.id, &mut r.entry.art);
+        }
+        return Json(rows).into_response();
+    }
     let mut games = crate::library::all_games();
-    if let Some(provider) = q.provider.filter(|p| !p.is_empty()) {
-        games.retain(|g| g.provider.as_deref() == Some(provider.as_str()));
-    }
-    if let Some(platform) = q.platform.filter(|p| !p.is_empty()) {
-        games.retain(|g| {
-            g.meta
-                .platform
-                .as_deref()
-                .is_some_and(|p| p.eq_ignore_ascii_case(&platform))
-        });
-    }
+    games.retain(|g| matches_query(g, &q));
     // Rewrite provider entries' local-file art into host art-proxy URLs so a client fetches covers
     // from the host (a provider like Playnite stores on-host paths; the payload stays tiny at any
     // library size, and the client never sees an unreachable `C:\…`).
@@ -103,16 +118,97 @@ pub(crate) async fn get_library(
     // a client picks a title by ID and the host resolves the recipe itself (`resolve_launch`),
     // which is the invariant that stops a client injecting a command in the first place. The
     // `kind` stays, so "this is launchable, and how" still renders.
-    if !lane.may_set_privileged_fields() {
-        for g in &mut games {
-            if let Some(l) = g.launch.as_mut() {
-                if l.kind == "command" {
-                    l.value.clear();
-                }
+    //
+    // Unconditional now: the operator's lane returned above, so reaching here IS "some lane but
+    // theirs". Leaving the old `if !lane.may_set_privileged_fields()` would read as though an
+    // unredacted path still existed here, and would quietly stop redacting if that early return
+    // ever moved.
+    for g in &mut games {
+        if let Some(l) = g.launch.as_mut() {
+            if l.kind == "command" {
+                l.value.clear();
             }
         }
     }
-    Json(games)
+    Json(games).into_response()
+}
+
+/// The `?provider=` / `?platform=` narrowing, shared by both lane arms so they cannot drift.
+fn matches_query(g: &crate::library::GameEntry, q: &LibraryQuery) -> bool {
+    if let Some(provider) = q.provider.as_deref().filter(|p| !p.is_empty()) {
+        if g.provider.as_deref() != Some(provider) {
+            return false;
+        }
+    }
+    if let Some(platform) = q.platform.as_deref().filter(|p| !p.is_empty()) {
+        if !g
+            .meta
+            .platform
+            .as_deref()
+            .is_some_and(|p| p.eq_ignore_ascii_case(platform))
+        {
+            return false;
+        }
+    }
+    true
+}
+
+/// Request body for `setLibraryEntryHidden`.
+#[derive(Deserialize, ToSchema)]
+pub(crate) struct HiddenToggle {
+    /// Whether this title should be hidden from every play surface.
+    hidden: bool,
+}
+
+/// What `setLibraryEntryHidden` echoes back.
+#[derive(Serialize, ToSchema)]
+pub(crate) struct HiddenState {
+    /// The entry id the call addressed.
+    id: String,
+    /// Its visibility after the call.
+    hidden: bool,
+}
+
+/// Hide or un-hide one library title
+///
+/// Curation, not access control: a hidden title disappears from every play surface — the console
+/// grid on a client, native clients, the GameStream app list, and launch resolution — while nothing
+/// is deleted and un-hiding restores it immediately. The operator's own console still lists it
+/// (flagged `hidden`) so it can be brought back.
+///
+/// Keyed by the entry's stable `<store>:<external_id>` id, which survives re-scans and reconciles by
+/// construction (D2). The id is **not** validated against the current library on purpose: a title
+/// can be legitimately absent at this moment (launcher closed, plugin mid-sync, drive unmounted),
+/// and refusing the operator's choice in that window would be worse than storing an id that
+/// currently matches nothing. Emits `library.changed` (source = the store) only on a real change.
+#[utoipa::path(
+    put,
+    path = "/library/hidden/{id}",
+    tag = "library",
+    operation_id = "setLibraryEntryHidden",
+    params(("id" = String, Path, description = "The library entry id (e.g. `steam:70`)")),
+    request_body = HiddenToggle,
+    responses(
+        (status = OK, description = "Stored; the entry's visibility after the call", body = HiddenState),
+        (status = BAD_REQUEST, description = "Empty entry id", body = ApiError),
+        (status = UNAUTHORIZED, description = "Missing or invalid bearer token", body = ApiError),
+        (status = INTERNAL_SERVER_ERROR, description = "Could not persist the settings", body = ApiError),
+    )
+)]
+pub(crate) async fn set_library_entry_hidden(
+    Path(id): Path<String>,
+    ApiJson(toggle): ApiJson<HiddenToggle>,
+) -> Response {
+    if id.trim().is_empty() {
+        return api_error(StatusCode::BAD_REQUEST, "entry id must not be empty");
+    }
+    match crate::library::set_entry_hidden(&id, toggle.hidden) {
+        Ok(hidden) => {
+            tracing::info!(entry = %id, hidden, "management API: library entry visibility set");
+            Json(HiddenState { id, hidden }).into_response()
+        }
+        Err(e) => api_error(StatusCode::INTERNAL_SERVER_ERROR, &e.to_string()),
+    }
 }
 
 /// Request body for `setLibraryScanner`.
@@ -205,7 +301,9 @@ pub(crate) async fn create_custom_game(
     if input.title.trim().is_empty() {
         return api_error(StatusCode::BAD_REQUEST, "title must not be empty");
     }
-    if let Some(denied) = check_entry_fields(lane, &input.art, input.launch.as_ref(), &input.prep) {
+    if let Some((_, denied)) =
+        check_entry_fields(lane, &input.art, input.launch.as_ref(), &input.prep)
+    {
         return denied;
     }
     match crate::library::add_custom(input) {
@@ -238,7 +336,9 @@ pub(crate) async fn update_custom_game(
     if input.title.trim().is_empty() {
         return api_error(StatusCode::BAD_REQUEST, "title must not be empty");
     }
-    if let Some(denied) = check_entry_fields(lane, &input.art, input.launch.as_ref(), &input.prep) {
+    if let Some((_, denied)) =
+        check_entry_fields(lane, &input.art, input.launch.as_ref(), &input.prep)
+    {
         return denied;
     }
     use crate::library::MutateOutcome;
@@ -364,11 +464,14 @@ pub(crate) async fn reconcile_provider_entries(
     // Every entry in the payload, not just the first — a reconcile replaces a whole entry set, so
     // one privileged field anywhere in it is one command execution.
     for (i, e) in inputs.iter().enumerate() {
-        if let Some(denied) = check_entry_fields(lane, &e.art, e.launch.as_ref(), &e.prep) {
+        if let Some((reason, denied)) = check_entry_fields(lane, &e.art, e.launch.as_ref(), &e.prep)
+        {
             tracing::warn!(
                 provider,
                 index = i,
-                "library reconcile refused: payload carries a field this lane may not set"
+                title = %e.title,
+                reason = %reason,
+                "library reconcile refused"
             );
             return denied;
         }

crates/punktfunk-host/src/mgmt/plugins.rs

@@ -286,6 +286,38 @@ pub(crate) fn live_plugin_ids() -> Vec<String> {
     registry().live_ids()
 }
 
+/// The loopback `{port, secret}` a live plugin serves its UI on — the credential the **host itself**
+/// presents when it asks a library plugin what to run for one of its `plugin`-kind launch entries
+/// ([`crate::library::ask_plugin_launch`]).
+///
+/// The same lookup the console proxy gets from `GET /plugins/{id}/ui-credential`, exposed in-process
+/// so the launch path never round-trips through the management API to reach a port this process
+/// already holds. `None` for an unknown, expired, or UI-less plugin — which the launch path reports
+/// as "no recipe", exactly like any other unresolvable entry.
+pub(crate) fn ui_credential(id: &str) -> Option<UiCredential> {
+    registry().credential(id)
+}
+
+/// Put a live UI registration in the registry directly — **test only**, so the launch path
+/// ([`crate::library::ask_plugin_launch`]) can be driven against a stub server without standing up
+/// the whole management router just to reach `PUT /plugins/{id}`.
+#[cfg(test)]
+pub(crate) fn register_ui_for_test(id: &str, port: u16, secret: &str) {
+    registry().upsert(
+        id,
+        Valid {
+            title: id.to_string(),
+            version: None,
+            ui: Some(StoredUi {
+                port,
+                secret: secret.to_string(),
+                icon: None,
+            }),
+            category: None,
+        },
+    );
+}
+
 // ---------------------------------------------------------------- validation
 
 /// A plugin id: `definePlugin`'s kebab-case name (`^[a-z][a-z0-9-]*$`, ≤64) — the same regex the SDK

crates/punktfunk-host/src/mgmt/tests.rs

@@ -1198,6 +1198,10 @@ fn every_route_is_classified_for_the_plugin_and_cert_lanes() {
         ("GET", "/api/v1/library/art/{id}/{kind}", true, true),
         ("GET", "/api/v1/library/scanners", true, false),
         ("PUT", "/api/v1/library/scanners/{id}", true, false),
+        // Hiding a title is the OPERATOR curating their own library: a plugin has no business
+        // deciding what the operator sees, and a paired client must not be able to hide a game on
+        // the host it is streaming from. Neither lane, unlike the scanner toggle above.
+        ("PUT", "/api/v1/library/hidden/{id}", false, false),
         ("POST", "/api/v1/library/custom", true, false),
         ("PUT", "/api/v1/library/custom/{id}", true, false),
         ("DELETE", "/api/v1/library/custom/{id}", true, false),
@@ -2048,6 +2052,40 @@ async fn library_scanner_list_and_unknown_toggle() {
     );
 }
 
+/// A library id is `<store>:<external_id>`, so the hide route's path segment CONTAINS A COLON —
+/// and for Heroic (`heroic:legendary:<hash>`) it contains two.
+///
+/// This is the one thing about the endpoint that could be silently wrong: if the router did not
+/// match, or split on the colon, the console's hide button would 404 against an id the host itself
+/// produced. Asserting "not 404" is the whole point, so the body is deliberately INVALID — that
+/// stops at the JSON layer with a 4xx and never reaches the handler, which would otherwise write
+/// `library-hidden.json` into the developer's real config dir (the same reason the toggle test
+/// above only exercises its rejection path).
+#[tokio::test]
+async fn hide_route_matches_ids_containing_colons() {
+    let app = test_app(test_state(), None);
+    let put = |id: &str| {
+        axum::http::Request::put(format!("/api/v1/library/hidden/{id}"))
+            .header(axum::http::header::CONTENT_TYPE, "application/json")
+            // Not a `HiddenToggle` — rejected before the handler runs.
+            .body(Body::from(serde_json::json!({"nope": 1}).to_string()))
+            .unwrap()
+    };
+
+    for id in ["steam:70", "custom:abc", "heroic:legendary:fc0b13b7"] {
+        let (s, json) = send(&app, put(id)).await;
+        assert_ne!(
+            s,
+            StatusCode::NOT_FOUND,
+            "`{id}` must ROUTE — a colon is a legal path character and every library id has one: {json}"
+        );
+        assert!(
+            s.is_client_error(),
+            "a body that is not a HiddenToggle must be refused, not accepted: {s} {json}"
+        );
+    }
+}
+
 // ------------------------------------------------------------------ library providers
 
 /// Provider reconcile validation (the write path itself is unit-tested in `library::custom`

crates/punktfunk-host/src/native.rs

@@ -1148,7 +1148,12 @@ async fn serve_session(
     // path verdict (WARN + learned clamp for the next session on a constrained path; clears
     // a stale clamp on a healthy one) — and, with the driver above, heal or grow THIS
     // session mid-stream. Bounded ~10 s task unless a jumbo grow leaves it as revert guard.
-    wire_mtu::spawn_watch(conn.clone(), welcome.shard_payload as usize, shard_reneg);
+    wire_mtu::spawn_watch(
+        conn.clone(),
+        welcome.shard_payload as usize,
+        hello.max_shard_payload,
+        shard_reneg,
+    );
     // Negotiated cursor forwarding: the HOST_CAP_CURSOR bit the Welcome advertised, read back
     // rather than recomputed (`handshake::cursor_forward` computed it once, with the encoder
     // blend-capability gate — re-running it here could drift, and would re-probe).
@@ -1507,11 +1512,17 @@ async fn serve_session(
     // launcher's on-disk metadata, and the data plane needs three things out of it — what to run, what
     // to call the title, and how to recognize its process once a launcher has handed off
     // (design/session-game-lifetime.md §4).
-    let launch_target =
-        hello
-            .launch
-            .as_deref()
-            .and_then(|id| match crate::library::resolve_launch(id) {
+    //
+    // On a blocking thread: a `plugin`-kind entry resolves by asking the plugin that owns it over
+    // loopback (`library::ask_plugin_launch`), and this is an async context.
+    let launch_target = match hello.launch.as_deref() {
+        None => None,
+        Some(id) => {
+            let owned = id.to_string();
+            match tokio::task::spawn_blocking(move || crate::library::resolve_launch(&owned))
+                .await
+                .context("resolve the session's library launch")?
+            {
                 Some(t) => {
                     tracing::info!(
                         launch_id = id,
@@ -1528,7 +1539,9 @@ async fn serve_session(
                     );
                     None
                 }
-            });
+            }
+        }
+    };
     #[cfg(target_os = "windows")]
     let launch_for_dp = launch_target.as_ref().and(hello.launch.clone());
     #[cfg(not(target_os = "windows"))]

crates/punktfunk-host/src/native/compositor.rs

@@ -33,6 +33,52 @@ fn pick_compositor(
     }
 }
 
+/// Is this connect pinned at a compositor that is not actually running?
+///
+/// Pure (the I/O shell passes in the observed liveness) so the interaction is unit-tested, because
+/// it is invisible from the outside: an operator pin puts its backend into
+/// [`crate::vdisplay::available`] unconditionally AND skips `apply_session_env`'s
+/// `XDG_CURRENT_DESKTOP` scrub, so [`pick_compositor`] hands back a compositor that may be a corpse
+/// and its `None` (recover) arm can never fire. [`Compositor::Gamescope`] is exempt — it stands its
+/// own session up, which is the whole reason a headless box pins it.
+#[cfg(not(target_os = "windows"))]
+fn pinned_at_a_dead_session(
+    overridden: bool,
+    chosen: crate::vdisplay::Compositor,
+    live: crate::vdisplay::ActiveKind,
+) -> bool {
+    overridden && chosen.needs_live_session() && live == crate::vdisplay::ActiveKind::None
+}
+
+/// The handshake error for "no graphical session is live for this uid" — the state a compositor
+/// crash leaves behind (gnome-shell SIGSEGV → GDM greeter, whose auto-login is once-per-boot, so the
+/// box would otherwise need a walk-up or a reboot).
+///
+/// Fires the operator's recovery hook (debounced) on the way out when one is configured, so the
+/// client's retry a few seconds later lands in a recovered desktop. `pinned` names the
+/// `PUNKTFUNK_COMPOSITOR` value when the pin is what got us here, so the message can say which knob
+/// to change rather than the generic advice to *set* the knob that caused it.
+#[cfg(not(target_os = "windows"))]
+fn no_live_session(pinned: Option<&str>) -> anyhow::Error {
+    if crate::vdisplay::try_recover_session() {
+        return anyhow::anyhow!(
+            "no live graphical session for this uid — host session recovery launched \
+             (PUNKTFUNK_RECOVER_SESSION_CMD); retry in a few seconds"
+        );
+    }
+    match pinned {
+        Some(pin) => anyhow::anyhow!(
+            "PUNKTFUNK_COMPOSITOR={pin} pins this host to a backend that can only attach to an \
+             already-running compositor, and no graphical session is live for this uid — start a \
+             session, pin `gamescope` (it stands its own up), or set PUNKTFUNK_RECOVER_SESSION_CMD"
+        ),
+        None => anyhow::anyhow!(
+            "no usable compositor (no live graphical session for this uid; set \
+             PUNKTFUNK_COMPOSITOR or start a desktop/gaming session)"
+        ),
+    }
+}
+
 /// Resolve the client's compositor preference to a concrete backend (the I/O shell around
 /// [`pick_compositor`]): enumerate what's available, auto-detect the default, pick, and log
 /// whether the explicit request was honored or fell back. Runs blocking probes — call off the
@@ -61,13 +107,21 @@ pub(super) fn resolve_compositor(
         // Explicit operator override (legacy / CI / forcing a backend for a test) wins and is assumed
         // to come with a hand-set env — don't retarget the process env in that case.
         let overridden = pf_host_config::config().compositor.is_some();
+        // Liveness is read on BOTH paths. The auto path retargets the process env at the live
+        // session (below); the PINNED path needs it too, because a pin names a BACKEND, not a
+        // running session — and a pin whose compositor has died used to be indistinguishable from a
+        // healthy one here (it skips `apply_session_env`'s `XDG_CURRENT_DESKTOP` scrub and lands
+        // itself in `available()`, so `pick_compositor` could never return `None`). That combination
+        // marched every client through 8 doomed `create` retries and left the operator's
+        // `PUNKTFUNK_RECOVER_SESSION_CMD` unreachable — see the `needs_live_session` gate below.
+        let active = crate::vdisplay::detect_active_session();
         let detected = if overridden {
             crate::vdisplay::detect().ok()
         } else {
             // Auto: detect the LIVE session (Gaming vs Desktop) and retarget the process env at it so
             // every backend (video capture + input) this connect opens against the active session —
             // this is the state machine that lets one host follow a Bazzite box across Gaming↔Desktop.
-            let active = crate::vdisplay::detect_active_session();
+            //
             // A4: if the compositor instance changed since the last connect (an idle-time Game↔Desktop
             // switch), bump the epoch + invalidate the old backend's kept displays so this connect never
             // reuses a node id from the dead instance.
@@ -84,14 +138,36 @@ pub(super) fn resolve_compositor(
         // under `game_session=dedicated` (gamescope confirmed available) forces its OWN headless
         // gamescope spawn at the client's mode, overriding the detected desktop/game-mode backend. The
         // env was already retargeted above (for XDG_RUNTIME_DIR / the PipeWire daemon); we just pin the
-        // backend + input to the spawn sub-mode. Skipped under an explicit operator compositor pin.
-        if dedicated_launch && !overridden {
-            let route = crate::vdisplay::apply_input_env(Compositor::Gamescope, true);
-            tracing::info!(
-                ?route,
-                "dedicated game session — routing to a headless gamescope spawn at the client mode"
-            );
-            return Ok((Compositor::Gamescope, route));
+        // backend + input to the spawn sub-mode. An explicit operator compositor pin still outranks
+        // it — but says so out loud (below), because a silent veto is indistinguishable from the
+        // feature being broken.
+        if dedicated_launch {
+            if overridden {
+                // The pin still wins (it is the operator's explicit, hand-configured knob), but it
+                // must NEVER win silently: the console goes on displaying `game_session=dedicated`
+                // while every launch lands in the pinned session instead, and nothing in the log
+                // connects the two. That cost a full triage on a box whose `PUNKTFUNK_COMPOSITOR`
+                // was a forgotten validation leftover — the setting had never once taken effect and
+                // the only evidence was the ABSENCE of the info! line below.
+                tracing::warn!(
+                    pin = pf_host_config::config()
+                        .compositor
+                        .as_deref()
+                        .unwrap_or("-"),
+                    "game_session=dedicated asked for this launch's OWN headless gamescope, but \
+                     PUNKTFUNK_COMPOSITOR pins this host to a backend — the operator pin wins and \
+                     the game launches into the pinned session instead. Unset PUNKTFUNK_COMPOSITOR \
+                     to get dedicated game sessions."
+                );
+            } else {
+                let route = crate::vdisplay::apply_input_env(Compositor::Gamescope, true);
+                tracing::info!(
+                    ?route,
+                    "dedicated game session — routing to a headless gamescope spawn at the client \
+                     mode"
+                );
+                return Ok((Compositor::Gamescope, route));
+            }
         }
         let available = crate::vdisplay::available();
         let chosen = match pick_compositor(pref, &available, detected) {
@@ -112,23 +188,18 @@ pub(super) fn resolve_compositor(
                 );
                 Compositor::Gamescope
             }
-            None => {
-                // The state a compositor crash leaves behind (gnome-shell
-                // SIGSEGV → GDM greeter, whose auto-login is once-per-boot). If the operator
-                // configured a recovery hook, fire it (debounced) and tell the client to retry:
-                // its next knock lands in the recovered desktop.
-                if crate::vdisplay::try_recover_session() {
-                    anyhow::bail!(
-                        "no live graphical session for this uid — host session recovery launched \
-                         (PUNKTFUNK_RECOVER_SESSION_CMD); retry in a few seconds"
-                    );
-                }
-                anyhow::bail!(
-                    "no usable compositor (no live graphical session for this uid; set \
-                     PUNKTFUNK_COMPOSITOR or start a desktop/gaming session)"
-                );
-            }
+            None => return Err(no_live_session(None)),
         };
+        // Same dead-session exit, reached the other way: a pin puts its backend in `available()`
+        // unconditionally, so `pick_compositor` above can hand back a compositor that is not
+        // actually running and the `None` arm never fires. Check the backend's own requirement
+        // against observed liveness instead of trusting the pin. Gamescope is exempt — it stands
+        // its own session up, which is the whole point of pinning it on a headless box.
+        if pinned_at_a_dead_session(overridden, chosen, active.kind) {
+            return Err(no_live_session(
+                pf_host_config::config().compositor.as_deref(),
+            ));
+        }
         // Point input at the same backend and resolve the gamescope sub-mode (managed where the
         // session infra exists, attach to a foreign gamescope, else per-session bare spawn). The
         // route travels back to the caller as a VALUE and is carried on the backend instance — an
@@ -170,6 +241,44 @@ mod tests {
     use super::pick_compositor;
     use punktfunk_core::config::CompositorPref;
 
+    /// A pin at a compositor that ISN'T RUNNING must take the recovery exit rather than march the
+    /// client into a bring-up that can only fail.
+    ///
+    /// The regression this pins down: `PUNKTFUNK_COMPOSITOR=mutter` on a box whose gnome-shell had
+    /// segfaulted. The pin put Mutter in `available()` and suppressed the `XDG_CURRENT_DESKTOP`
+    /// scrub, so every connect "resolved" happily and then spent 8 retries on
+    /// `RemoteDesktop.CreateSession: ServiceUnknown` — while the operator's
+    /// `PUNKTFUNK_RECOVER_SESSION_CMD` sat unreachable behind a `None` arm that could never fire.
+    #[cfg(not(target_os = "windows"))]
+    #[test]
+    fn a_pin_at_a_dead_session_recovers_instead_of_retrying() {
+        use super::pinned_at_a_dead_session as dead;
+        use crate::vdisplay::{ActiveKind, Compositor::*};
+        // The bug: pinned to a desktop backend with nothing live for this uid.
+        assert!(dead(true, Mutter, ActiveKind::None));
+        assert!(dead(true, Kwin, ActiveKind::None));
+        assert!(dead(true, Wlroots, ActiveKind::None));
+        assert!(dead(true, Hyprland, ActiveKind::None));
+        // Pinned but the session IS up — the ordinary case, must not bail.
+        assert!(!dead(true, Mutter, ActiveKind::DesktopGnome));
+        // Gamescope stands its own session up from nothing: pinning it on a headless box is a
+        // SUPPORTED setup, not a dead session. (This is the .21 no-login workaround — never break it.)
+        assert!(!dead(true, Gamescope, ActiveKind::None));
+        // Unpinned is untouched: the auto path already reaches `pick_compositor`'s `None` arm via
+        // `compositor_for_kind(ActiveKind::None)`, and it owns the managed-takeover case.
+        assert!(!dead(false, Mutter, ActiveKind::None));
+    }
+
+    /// gamescope is the ONLY backend that can serve a connect with no session already running.
+    #[test]
+    fn only_gamescope_survives_a_dead_session() {
+        use crate::vdisplay::Compositor::*;
+        assert!(!Gamescope.needs_live_session());
+        for c in [Mutter, Kwin, Wlroots, Hyprland] {
+            assert!(c.needs_live_session(), "{c:?} needs a live compositor");
+        }
+    }
+
     #[test]
     fn compositor_resolution_precedence() {
         use crate::vdisplay::Compositor::*;

crates/punktfunk-host/src/native/handshake.rs

@@ -148,7 +148,6 @@ pub(super) async fn negotiate(
     Option<crate::vdisplay::GamescopeRoute>,
     Option<super::stream::PrepHandle>,
 )> {
-    let peer = conn.remote_address();
     let mut hello = Hello::decode(first).map_err(|e| anyhow!("Hello decode: {e:?}"))?;
     if hello.abi_version != punktfunk_core::WIRE_VERSION {
         close_rejected(
@@ -270,13 +269,15 @@ pub(super) async fn negotiate(
             // id must fall back to normal auto routing, not a blank "sleep infinity" gamescope
             // (review #9). (dedicated is Linux-only, and only there does `resolve_launch` carry a
             // command — on Windows the concrete process is resolved at launch time instead.)
+            // `launch_is_resolvable`, not a full `resolve_launch`: a `plugin`-kind entry's command
+            // is fetched from the owning plugin over loopback, and this runs on the async path. The
+            // cheap check answers the only question asked here (does this tile launch anything?)
+            // without a blocking call — see `library::launch_is_resolvable`.
             #[cfg(not(target_os = "windows"))]
             let has_resolvable_launch = hello
                 .launch
                 .as_deref()
-                .and_then(crate::library::resolve_launch)
-                .and_then(|t| t.command)
-                .is_some();
+                .is_some_and(crate::library::launch_is_resolvable);
             #[cfg(target_os = "windows")]
             let has_resolvable_launch = false;
             let dedicated = crate::vdisplay::wants_dedicated_game_session(has_resolvable_launch);
@@ -495,6 +496,11 @@ pub(super) async fn negotiate(
     let (data_sock, direct) = bind_data_socket(data_port)?;
     let udp_port = data_sock.local_addr()?.port();
 
+    // The session's video geometry (see the `shard_payload` field below). Resolved before the
+    // Welcome struct because a path a previous session proved jumbo is given a bounded moment
+    // to re-prove itself live on THIS connection — the awaited part of `negotiated_shard_payload`.
+    let shard_payload = wire_mtu::negotiated_shard_payload(conn, hello.max_shard_payload).await;
+
     let mut key = [0u8; 16];
     rand::thread_rng().fill_bytes(&mut key);
     // Fresh per-session salt alongside the fresh key. GCM nonce uniqueness only *requires* one
@@ -546,14 +552,15 @@ pub(super) async fn negotiate(
         // hardcoded 1452 overshot the v4 ceiling (its math forgot the header/crypto ride
         // inside the UDP payload) and silently IP-fragmented EVERY video datagram, doubling
         // per-datagram loss on Wi-Fi — the "100 Mbps badly fails on the phone" root cause.
-        // Negotiated, so the client follows. Jumbo (≈8900) is a future negotiated bump (needs
-        // MAX_DATAGRAM_BYTES raised + end-to-end 9000 MTU).
-        // Resolution order (wire_mtu.rs): `PUNKTFUNK_WIRE_MTU` operator override, then a path
-        // budget learned from a prior session whose QUIC MTU discovery settled below the
-        // video-datagram ceiling (the "VPN on the host blackholes every video packet" field
-        // shape — small flows pass, the stream is an endless black screen), then this family
-        // default. Healthy paths take the default branch and are byte-identical to before.
-        shard_payload: wire_mtu::negotiated_shard_payload(peer.ip()) as u16,
+        // Negotiated, so the client follows.
+        // Resolution order (wire_mtu.rs): a JUMBO start (≈8900) on a path a previous session
+        // proved AND this connection has just re-proved live, then the `PUNKTFUNK_WIRE_MTU`
+        // operator override, then a path budget learned from a prior session whose QUIC MTU
+        // discovery settled below the video-datagram ceiling (the "VPN on the host blackholes
+        // every video packet" field shape — small flows pass, the stream is an endless black
+        // screen), then this family default. Healthy paths take the default branch and are
+        // byte-identical to before.
+        shard_payload: shard_payload as u16,
         encrypt: true,
         key,
         salt,

crates/punktfunk-host/src/native/stream.rs

@@ -1553,6 +1553,46 @@ pub(super) fn virtual_stream(ctx: SessionContext, prepared: Option<PreparedDispl
              encoder supports chunked output"
         );
     }
+    // A mode switch the control task accepted BEFORE the pipeline was built (the client connects at
+    // one mode and immediately asks for its real one — a fractional-scale panel resolving its native
+    // pixel size does exactly this, ~3 s ahead of bring-up finishing) used to be served the long way
+    // round: build the whole pipeline at the now-stale mode, then immediately rebuild at the new one
+    // in the loop below. That wastes a display create + capture attach + encoder open on every such
+    // connect, and on GNOME it is actively destructive — the rebuild is create-before-drop, so two
+    // `RecordVirtual` monitors ~400 ms apart segfault mutter 50.4 inside
+    // `meta_monitor_manager_rebuild`, taking down the whole desktop session (and with it the game
+    // just launched into it, which then looks like the GAME crashed). Adopt the newest queued mode
+    // here and build ONCE.
+    //
+    // Only on the inline path: a PREPARED pipeline is already built at the old mode, so adopting a
+    // new `mode` there would just make this variable disagree with the display that exists. Those
+    // sessions keep the rebuild-in-the-loop behavior. No accept ack is owed either way — the
+    // client's mode slot already flipped when control accepted the switch (it acks on accept, not
+    // on rebuild); the H2/H3 *correction* ack the rebuild would have sent is preserved below.
+    let mut mode = mode;
+    let mut adopted_at_bringup = false;
+    if prepared.is_none() {
+        let mut queued = None;
+        while let Ok(m) = reconfig.try_recv() {
+            queued = Some(m);
+        }
+        if let Some(m) = queued.filter(|m| *m != mode) {
+            adopted_at_bringup = true;
+            tracing::info!(
+                stale = ?mode,
+                adopted = ?m,
+                "a mode switch was accepted before bring-up finished — building at the new mode \
+                 instead of building twice"
+            );
+            mode = m;
+            // Mirror the loop's rebuild: PyroWave's Automatic bitrate is a per-mode ~1.6 bpp pin, so
+            // a resolution change moves the operating point. Explicit client rates stay put.
+            if bitrate_auto && plan.codec == crate::encode::Codec::PyroWave {
+                bitrate_kbps =
+                    resolve_bitrate_kbps_for(plan.codec, 0, &mode, plan.chroma, plan.bit_depth);
+            }
+        }
+    }
     tracing::info!(
         compositor = compositor.id(),
         ?mode,
@@ -1666,6 +1706,20 @@ pub(super) fn virtual_stream(ctx: SessionContext, prepared: Option<PreparedDispl
         &live_bitrate,
         &retarget_tx,
     );
+    // H2/H3 correction, carried over from the rebuild this bring-up replaced: the client APPLIED
+    // the mode when control accepted it, but the backend may have honored a different one (KWin
+    // caps a virtual output's refresh; a fallback delivers the size the source actually produces).
+    // Only for a mode adopted at bring-up — an ordinary connect's mode came from the Welcome, not
+    // from an accept the client has already acted on, so it is not owed a correction here.
+    if adopted_at_bringup {
+        let actual = delivered_mode(frame.width, frame.height, interval);
+        if actual != mode {
+            let _ = reconfig_result_tx.send(Reconfigured {
+                accepted: true,
+                mode: actual,
+            });
+        }
+    }
 
     // Capture is live — launch the requested title so it renders onto the streamed output and
     // grabs focus. Windows spawns the library id into the interactive user session; Linux spawns

crates/punktfunk-host/src/native/wire_mtu.rs

@@ -24,6 +24,14 @@
 //! - **Heal** — the next handshake from that peer clamps `shard_payload` to the recorded
 //!   budget, so a reconnect fixes the stream. A later session that reaches the ceiling erases
 //!   the record (the learn/heal loop is self-correcting in both directions).
+//! - **Grow** (PW7a) — the mirror image, for the jumbo half: a connection whose discovery
+//!   settles at the sealed JUMBO size has proven the path carries ~8.9 KB video datagrams, and
+//!   the next session on that same path *starts* there instead of at the 1500-byte default.
+//!   PyroWave sessions cannot be re-keyed mid-stream (the client's parse window is the
+//!   `Welcome` value, read once over the C ABI), so the session-start value is the ONLY way
+//!   they ever reach jumbo — and it is exactly where ~6× fewer datagrams per frame is worth
+//!   the most. See [`jumbo_session_start`] for why a remembered verdict alone is never
+//!   allowed to seal one byte above the default.
 
 use std::collections::HashMap;
 use std::net::IpAddr;
@@ -63,10 +71,155 @@ fn learned() -> &'static Mutex<HashMap<IpAddr, u16>> {
     LEARNED.get_or_init(|| Mutex::new(HashMap::new()))
 }
 
-/// The shard payload for a new session to `peer`: `PUNKTFUNK_WIRE_MTU` override, else the
-/// peer's learned path budget, else the family default (today's exact behavior). Logs whenever
-/// the result differs from the default.
-pub(super) fn negotiated_shard_payload(peer: IpAddr) -> usize {
+/// Identity of a PATH, not of a peer — the key the jumbo verdict is filed under.
+///
+/// The clamp above is keyed by peer IP alone, and that is safe *because being wrong is benign*:
+/// a stale clamp only makes video datagrams smaller than they had to be. A stale GROW is the
+/// opposite — one oversized datagram on a 1500-byte path is silently dropped, which is the
+/// "connects fine, black screen forever" shape this whole module exists to kill. So the grow
+/// keys strictly: a verdict earned over the host's 10 GbE NIC does not apply to the same peer
+/// IP reached over the host's Wi-Fi or a VPN adapter, because those are different routes with
+/// different MTUs.
+///
+/// `local` is `Connection::local_ip()` (the address the connection was actually received on);
+/// `None` where the platform can't report it, which degrades this key to the clamp's — safely,
+/// because the live re-proof in [`jumbo_session_start`] is what actually protects the grow.
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+struct PathKey {
+    local: Option<IpAddr>,
+    peer: IpAddr,
+}
+
+/// A path that a completed MTU-discovery search proved carries jumbo video datagrams.
+#[derive(Clone, Copy, Debug)]
+struct JumboVerdict {
+    /// The settled UDP-payload budget the proof measured.
+    udp_budget: u16,
+    /// The operator's jumbo target when the proof was taken. A changed `PUNKTFUNK_JUMBO` /
+    /// `PUNKTFUNK_WIRE_MTU` invalidates it rather than being silently reinterpreted.
+    target_wire_mtu: usize,
+    /// When it was taken ([`JUMBO_VERDICT_TTL`]).
+    at: std::time::Instant,
+}
+
+/// How long a jumbo verdict may be redeemed for. Contrary evidence erases it long before this
+/// (any settle below the sealed target, on any later session over the same path — the same
+/// self-correction the clamp has), so the TTL is not the safety mechanism; it is a bound on how
+/// stale an *unrefreshed* memory can get, for the case where the path changes while no session
+/// is running.
+const JUMBO_VERDICT_TTL: std::time::Duration = std::time::Duration::from_secs(6 * 3600);
+
+/// How long the `Welcome` may wait for THIS connection's MTU discovery to re-prove a jumbo
+/// path.
+///
+/// The wait is structural, not laziness: every connection restarts discovery from ~1200 bytes,
+/// so the live proof the grow requires does not exist yet when the `Welcome` is built — and the
+/// binary search up to sealed-jumbo needs an ACKED probe per step, each of which a peer may sit
+/// on for its ack delay. Without a wait the gate would never pass and the feature would be dead.
+///
+/// It is honestly on the bring-up critical path (`handshake.rs` sends the `Welcome` and only
+/// THEN kicks the display prep), so it is bounded, returns the instant the proof lands, and is
+/// entered ONLY for a path a previous session already proved jumbo — i.e. an opted-in operator
+/// on a jumbo LAN, never anyone else. The worst case (the full wait, no proof) is the moved
+/// laptop, and it is self-limiting: that session's watcher erases the verdict, so the next
+/// connect doesn't wait at all.
+const JUMBO_PROOF_WAIT: std::time::Duration = std::time::Duration::from_millis(300);
+const JUMBO_PROOF_POLL: std::time::Duration = std::time::Duration::from_millis(10);
+
+/// Proven-jumbo paths. Same lifetime rules as [`learned`] — in-memory, re-earned in one session
+/// after a host restart.
+fn jumbo_verdicts() -> &'static Mutex<HashMap<PathKey, JumboVerdict>> {
+    static JUMBO: OnceLock<Mutex<HashMap<PathKey, JumboVerdict>>> = OnceLock::new();
+    JUMBO.get_or_init(|| Mutex::new(HashMap::new()))
+}
+
+fn path_key(conn: &quinn::Connection) -> PathKey {
+    PathKey {
+        local: conn.local_ip(),
+        peer: conn.remote_address().ip(),
+    }
+}
+
+/// Everything the session-start jumbo decision reads. Every field but `proven_udp_budget` is
+/// observed on THIS connection during THIS handshake — which is the point (see
+/// [`jumbo_session_start`]).
+#[derive(Clone, Copy, Debug)]
+struct JumboStart {
+    /// The host operator's opt-in ([`jumbo_wire_mtu`]) — `None` = no jumbo, ever.
+    target_wire_mtu: Option<usize>,
+    /// `Hello::max_shard_payload`: the client's own receive ceiling (0 = legacy client, which
+    /// never gets a geometry it didn't ask for).
+    client_ceiling: u16,
+    /// `conn.stats().path.current_mtu` right now: the largest UDP payload quinn has had ACKED
+    /// on this connection.
+    live_udp_mtu: u16,
+    /// What a previous session over this same [`PathKey`] settled at, if any.
+    proven_udp_budget: Option<u16>,
+    /// The constrained-path clamp [`learned`] for this peer, if any. Contradictory evidence
+    /// (this peer black-screened on a small MTU recently) vetoes the grow — the two memories
+    /// are keyed differently and the safe one wins.
+    clamped_udp_budget: Option<u16>,
+}
+
+/// The jumbo shard payload a session to `peer` could use, or `None` when there is nothing to
+/// gain (no opt-in, a legacy/low client ceiling, or a target that isn't bigger than the family
+/// default). Shared by the decision, the wait, and the watcher so all three agree on the number.
+fn jumbo_target(
+    target_wire_mtu: Option<usize>,
+    client_ceiling: u16,
+    peer: IpAddr,
+) -> Option<usize> {
+    let mtu = target_wire_mtu?;
+    let t = jumbo_shard_payload_for(mtu, peer).min(client_ceiling as usize);
+    let t = t - t % 2; // FEC requires even shards
+    (t > mtu1500_shard_payload_for(peer)).then_some(t)
+}
+
+/// The session-START jumbo decision: `Some(shard_payload)` only when every gate below holds.
+///
+/// **Why a remembered verdict is never enough.** A laptop that proved jumbo on the wired LAN
+/// and comes back on Wi-Fi, a switch that lost its jumbo config, a client IP recycled by DHCP —
+/// all of them present a path that cannot carry an 8.9 KB datagram, and a PyroWave session
+/// sealed at that size cannot be re-keyed mid-stream, so it would black-screen for its whole
+/// life. The memory therefore only decides whether it is worth WAITING for a proof; what
+/// actually authorises the grow is `live_udp_mtu` — a datagram of exactly that size, acked by
+/// this client, on this connection, seconds ago. That is why this is as safe as the clamp
+/// despite the failure modes being opposite: a wrong memory cannot produce a jumbo `Welcome`,
+/// only a live measurement can.
+///
+/// The gates, in order: the host operator opted in; the client advertised enough receive
+/// headroom; the target beats the family default (nothing to gain otherwise); no constrained-path
+/// clamp contradicts it; a prior session over this exact path settled at or above the sealed
+/// target; and this connection has re-proven it live.
+fn jumbo_session_start(i: JumboStart, peer: IpAddr) -> Option<usize> {
+    let target = jumbo_target(i.target_wire_mtu, i.client_ceiling, peer)?;
+    let sealed = sealed_datagram_bytes(target);
+    if let Some(clamp) = i.clamped_udp_budget {
+        if (clamp as usize) < sealed {
+            return None;
+        }
+    }
+    if (i.proven_udp_budget? as usize) < sealed {
+        return None;
+    }
+    if (i.live_udp_mtu as usize) < sealed {
+        return None;
+    }
+    Some(target)
+}
+
+/// The shard payload for a new session on `conn`: a proven-jumbo grow, else the
+/// `PUNKTFUNK_WIRE_MTU` override, else the peer's learned path budget, else the family default
+/// (today's exact behavior). Logs whenever the result differs from the default.
+///
+/// `client_ceiling` is the client's `Hello::max_shard_payload`. Async only for the bounded
+/// [`JUMBO_PROOF_WAIT`], which is entered *only* on a path a previous session already proved
+/// jumbo — every other session resolves without awaiting anything.
+pub(super) async fn negotiated_shard_payload(
+    conn: &quinn::Connection,
+    client_ceiling: u16,
+) -> usize {
+    let peer = conn.remote_address().ip();
     let env = match std::env::var("PUNKTFUNK_WIRE_MTU") {
         Ok(v) => match v.trim().parse::<usize>() {
             Ok(mtu) => Some(mtu),
@@ -78,13 +231,80 @@ pub(super) fn negotiated_shard_payload(peer: IpAddr) -> usize {
         Err(_) => None,
     };
     let learned_budget = learned().lock().unwrap().get(&peer).copied();
-    resolve(env, learned_budget, peer)
+    let target_wire_mtu = jumbo_wire_mtu();
+    let proven_udp_budget = fresh_verdict(path_key(conn), target_wire_mtu);
+    let mut jumbo = JumboStart {
+        target_wire_mtu,
+        client_ceiling,
+        live_udp_mtu: conn.stats().path.current_mtu,
+        proven_udp_budget,
+        clamped_udp_budget: learned_budget,
+    };
+    // A proven path is worth waiting a moment for: MTU discovery starts when the handshake
+    // completes and needs an acked probe per binary-search step, so at `Welcome` time it may
+    // simply not have got there yet. Bounded, and only on paths that already proved it once.
+    let awaited_proof = proven_udp_budget
+        .and_then(|_| jumbo_target(target_wire_mtu, client_ceiling, peer))
+        .map(|t| sealed_datagram_bytes(t) as u16);
+    if let Some(sealed) = awaited_proof {
+        if jumbo.live_udp_mtu < sealed {
+            let t0 = std::time::Instant::now();
+            while t0.elapsed() < JUMBO_PROOF_WAIT {
+                tokio::time::sleep(JUMBO_PROOF_POLL).await;
+                jumbo.live_udp_mtu = conn.stats().path.current_mtu;
+                if jumbo.live_udp_mtu >= sealed {
+                    break;
+                }
+            }
+            tracing::debug!(
+                peer = %peer,
+                waited_ms = t0.elapsed().as_millis() as u64,
+                live_udp_mtu = jumbo.live_udp_mtu,
+                needed = sealed,
+                "wire MTU: waited for this connection to re-prove its jumbo path"
+            );
+        }
+    }
+    resolve(env, learned_budget, jumbo, peer)
 }
 
-/// Pure resolution (env override > learned budget > family default) — the tested core of
-/// [`negotiated_shard_payload`].
-fn resolve(env_wire_mtu: Option<usize>, learned_udp_budget: Option<u16>, peer: IpAddr) -> usize {
+/// The peer's jumbo verdict if it is still redeemable: same operator target, inside the TTL.
+/// A verdict that fails either test is dropped on the spot rather than left to rot.
+fn fresh_verdict(key: PathKey, target_wire_mtu: Option<usize>) -> Option<u16> {
+    let target = target_wire_mtu?;
+    let mut map = jumbo_verdicts().lock().unwrap();
+    let v = *map.get(&key)?;
+    if v.target_wire_mtu != target || v.at.elapsed() > JUMBO_VERDICT_TTL {
+        map.remove(&key);
+        return None;
+    }
+    Some(v.udp_budget)
+}
+
+/// Pure resolution (proven jumbo > env override > learned budget > family default) — the tested
+/// core of [`negotiated_shard_payload`].
+fn resolve(
+    env_wire_mtu: Option<usize>,
+    learned_udp_budget: Option<u16>,
+    jumbo: JumboStart,
+    peer: IpAddr,
+) -> usize {
     let default = mtu1500_shard_payload_for(peer);
+    // First, because the two are mutually exclusive by construction: `jumbo_wire_mtu()` only
+    // fires above 1500, and the env branch below CLAMPS to the family default, so a
+    // `PUNKTFUNK_WIRE_MTU=9000` operator would otherwise get 1408 and never a jumbo start.
+    if let Some(p) = jumbo_session_start(jumbo, peer) {
+        tracing::info!(
+            peer = %peer,
+            shard_payload = p,
+            default,
+            live_udp_mtu = jumbo.live_udp_mtu,
+            proven_udp_budget = jumbo.proven_udp_budget,
+            "wire MTU: session starts at the JUMBO shard — this path proved it in a previous \
+             session AND re-proved it live on this connection (~6× fewer datagrams per frame)"
+        );
+        return p;
+    }
     if let Some(mtu) = env_wire_mtu {
         let p = shard_payload_for_wire_mtu(mtu, peer);
         if p != default {
@@ -119,34 +339,73 @@ fn resolve(env_wire_mtu: Option<usize>, learned_udp_budget: Option<u16>, peer: I
 /// into a verdict — and, with a [`ShardReneg`] driver, act on it MID-SESSION
 /// (design/shard-payload-reneg.md Phase 2): a below-ceiling verdict shrinks the live wire at
 /// the ~3–10 s mark (session 1 heals instead of staying black), and a settled-at-jumbo
-/// verdict grows it, ack-gated, when the operator opted in. Spawned once per negotiated
-/// session; without a grow the task ends after the final sample (bounded ~10 s lifetime,
-/// holding only a cheap `Connection` handle) — after a grow it stays as the revert guard
-/// until the connection closes.
+/// verdict grows it, ack-gated, when the operator opted in. The same settled-at-jumbo reading
+/// also writes this path's next-session verdict (PW7a) — `client_ceiling` is the client's
+/// `Hello::max_shard_payload`, which decides what "jumbo" is worth proving for this peer.
+/// Spawned once per negotiated session; without a grow the task ends after the final sample
+/// (bounded ~10 s lifetime, holding only a cheap `Connection` handle) — after a grow, or on a
+/// session that STARTED jumbo, it stays as the revert guard until the connection closes.
 pub(super) fn spawn_watch(
     conn: quinn::Connection,
     session_shard_payload: usize,
+    client_ceiling: u16,
     reneg: Option<ShardReneg>,
 ) {
     tokio::spawn(async move {
         let peer = conn.remote_address().ip();
         let ceiling = video_datagram_udp_ceiling() as u16;
+        // The sealed size a JUMBO proof has to reach on this path (PW7a) — `None` unless the
+        // operator opted in AND this client advertised the headroom. Read once: the verdict
+        // records the target it was proven under, and the two must be the same number.
+        let target_wire_mtu = jumbo_wire_mtu();
+        let jumbo_proof =
+            jumbo_target(target_wire_mtu, client_ceiling, peer).map(sealed_datagram_bytes);
         // Discovery finishes in a handful of RTTs on a LAN (well under the first sample) but
         // needs a loss timeout per failed probe on a constrained path — the second sample
         // covers that with margin. Max, because discovery only ever raises `current_mtu`
         // (the post-grow revert guard below re-reads it live, where blackhole detection CAN
-        // lower it again).
+        // lower it again). Stop early only once nothing more is expected: with a jumbo opt-in
+        // the search keeps climbing past the 1500-byte ceiling, and stopping there would throw
+        // away the very measurement the proof needs.
+        let goal = jumbo_proof
+            .unwrap_or(ceiling as usize)
+            .max(ceiling as usize) as u16;
         let mut settled = 0u16;
         for wait_s in [3u64, 7] {
             tokio::time::sleep(std::time::Duration::from_secs(wait_s)).await;
             settled = settled.max(conn.stats().path.current_mtu);
-            if settled >= ceiling {
+            if settled >= goal {
                 break;
             }
         }
         // The wire this session is CURRENTLY sealed at — moves on a mid-session shrink/grow.
         let mut current = session_shard_payload;
         let mut reneg = reneg;
+        // PW7a bookkeeping, before anything else can return: this is where a jumbo path earns
+        // its next-session verdict — and, far more importantly, where it LOSES it. Recording
+        // needs a live connection that reached the sealed target; anything else (a lower
+        // settle, a connection that died before the window closed, i.e. exactly what a client
+        // staring at a black screen does) erases, so the next session falls back to the
+        // 1500-byte default and has to prove itself again from scratch.
+        if let Some(need) = jumbo_proof {
+            let key = path_key(&conn);
+            if settled as usize >= need && conn.close_reason().is_none() {
+                jumbo_verdicts().lock().unwrap().insert(
+                    key,
+                    JumboVerdict {
+                        udp_budget: settled,
+                        target_wire_mtu: target_wire_mtu.unwrap_or_default(),
+                        at: std::time::Instant::now(),
+                    },
+                );
+                tracing::info!(peer = %peer, discovered_udp_mtu = settled, needed = need,
+                    "wire MTU: this path carries JUMBO video datagrams — the next session over \
+                     it starts at the big shard (it still has to re-prove the path live)");
+            } else if jumbo_verdicts().lock().unwrap().remove(&key).is_some() {
+                tracing::info!(peer = %peer, discovered_udp_mtu = settled, needed = need,
+                    "wire MTU: jumbo verdict cleared — this path no longer proves it");
+            }
+        }
         if settled >= ceiling {
             // The path carries full-size video datagrams — erase any stale learned clamp so
             // the next session returns to the default wire.
@@ -154,6 +413,34 @@ pub(super) fn spawn_watch(
                 tracing::info!(peer = %peer,
                     "wire MTU: path re-measured at full size — learned clamp cleared");
             }
+            // …but "full size" is the 1500-byte ceiling, and this session may have STARTED
+            // above it (a PW7a jumbo start whose path changed since the proof, or a client
+            // that roamed onto a 1500-MTU link). Then every video datagram is dying right now.
+            // The verdict is already erased above; heal the live wire if this session can be
+            // re-keyed at all — a PyroWave client cannot (its parse window is the `Welcome`
+            // value), so for those the WARN plus a corrected next session is all there is.
+            if sealed_datagram_bytes(current) > settled as usize {
+                tracing::warn!(
+                    peer = %peer,
+                    discovered_udp_mtu = settled,
+                    shard_payload = current,
+                    "wire MTU: this session started at a JUMBO shard but the path does not \
+                     carry it — video datagrams are oversized for a hop, which streams as a \
+                     black screen with zero reported loss. The jumbo verdict for this path is \
+                     cleared: the next connect starts at the standard 1500-byte wire."
+                );
+                if let Some(r) = reneg.as_ref() {
+                    let back = shard_payload_for_udp_budget(settled as usize, peer);
+                    if back < current
+                        && r.change_tx.send(back as u16).is_ok()
+                        && r.apply_tx.send(back).is_ok()
+                    {
+                        tracing::info!(peer = %peer, shard_payload = back, was = current,
+                            "wire MTU: video re-keyed mid-session back to the standard wire");
+                        current = back;
+                    }
+                }
+            }
         } else {
             // A closed connection stops discovering, so a session that ended before the final
             // sample proves nothing (a healthy high-RTT path could still be mid-search): learn
@@ -203,12 +490,41 @@ pub(super) fn spawn_watch(
                 }
             }
         }
+        // PW7a revert guard for a session that STARTED jumbo and has no re-key channel (the
+        // PyroWave case, and the only reason the session-start grow exists). Nothing can save
+        // this session if the path stops fitting mid-stream — but the NEXT one must not repeat
+        // it, so keep sampling and drop the verdict the moment quinn's blackhole detection or
+        // a re-search says the path shrank. Cheap: one `Connection` handle, one sample per 5 s.
+        // Only for a session that is currently FITTING — one that already failed the check
+        // above has been warned about and had its verdict erased there.
+        if current > mtu1500_shard_payload_for(peer)
+            && reneg.is_none()
+            && sealed_datagram_bytes(current) <= settled as usize
+        {
+            loop {
+                tokio::time::sleep(std::time::Duration::from_secs(5)).await;
+                if conn.close_reason().is_some() {
+                    return;
+                }
+                let mtu_now = conn.stats().path.current_mtu;
+                if (mtu_now as usize) < sealed_datagram_bytes(current) {
+                    jumbo_verdicts().lock().unwrap().remove(&path_key(&conn));
+                    tracing::warn!(peer = %peer, discovered_udp_mtu = mtu_now,
+                        shard_payload = current,
+                        "wire MTU: the jumbo path this session started on stopped fitting — this \
+                         session cannot be re-keyed (chunk-aligned client parse window), so it \
+                         will not recover, but the verdict is cleared and the next connect \
+                         starts at the standard wire");
+                    return;
+                }
+            }
+        }
         // Phase 2 up-leg: jumbo grow — operator opt-in (PUNKTFUNK_JUMBO / PUNKTFUNK_WIRE_MTU
         // > 1500, which also raised the endpoint's probe ceiling so `settled` can even reach
         // here), client-advertised headroom, and a settled-at-jumbo proof. The grow is
         // ACK-GATED: not one sealed datagram above the old size leaves before the client's
         // ack, even though its buffers are statically sized — the rule must not erode.
-        let (Some(mtu), Some(r)) = (jumbo_wire_mtu(), reneg.as_mut()) else {
+        let (Some(mtu), Some(r)) = (target_wire_mtu, reneg.as_mut()) else {
             return;
         };
         let target = jumbo_shard_payload_for(mtu, peer).min(r.client_ceiling as usize);
@@ -275,34 +591,196 @@ mod tests {
 
     const V4: IpAddr = IpAddr::V4(Ipv4Addr::new(192, 168, 1, 2));
     const V6: IpAddr = IpAddr::V6(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 1));
+    /// No jumbo anywhere — what every session that isn't on an opted-in jumbo LAN passes.
+    const NO_JUMBO: JumboStart = JumboStart {
+        target_wire_mtu: None,
+        client_ceiling: 0,
+        live_udp_mtu: 0,
+        proven_udp_budget: None,
+        clamped_udp_budget: None,
+    };
+    /// A 9000-MTU LAN, a modern client, a path proven last session and re-proven live now.
+    fn proven_jumbo() -> JumboStart {
+        JumboStart {
+            target_wire_mtu: Some(9000),
+            client_ceiling: punktfunk_core::config::max_shard_payload() as u16,
+            live_udp_mtu: 8972,
+            proven_udp_budget: Some(8972),
+            clamped_udp_budget: None,
+        }
+    }
 
     #[test]
     fn default_when_nothing_known() {
-        assert_eq!(resolve(None, None, V4), mtu1500_shard_payload_for(V4));
-        assert_eq!(resolve(None, None, V6), mtu1500_shard_payload_for(V6));
+        assert_eq!(
+            resolve(None, None, NO_JUMBO, V4),
+            mtu1500_shard_payload_for(V4)
+        );
+        assert_eq!(
+            resolve(None, None, NO_JUMBO, V6),
+            mtu1500_shard_payload_for(V6)
+        );
     }
 
     #[test]
     fn env_override_beats_learned() {
         // 1280 wire − 28 IP/UDP − 64 header/crypto = 1188.
-        assert_eq!(resolve(Some(1280), Some(1472), V4), 1188);
+        assert_eq!(resolve(Some(1280), Some(1472), NO_JUMBO, V4), 1188);
     }
 
     #[test]
     fn learned_budget_clamps() {
         // A WARP-shaped path: 1280-byte UDP budget → 1280 − 64 = 1216.
-        assert_eq!(resolve(None, Some(1280), V4), 1216);
+        assert_eq!(resolve(None, Some(1280), NO_JUMBO, V4), 1216);
     }
 
     #[test]
     fn learned_at_or_above_ceiling_is_the_default_wire() {
-        assert_eq!(resolve(None, Some(1472), V4), mtu1500_shard_payload_for(V4));
-        assert_eq!(resolve(None, Some(2000), V4), mtu1500_shard_payload_for(V4));
+        assert_eq!(
+            resolve(None, Some(1472), NO_JUMBO, V4),
+            mtu1500_shard_payload_for(V4)
+        );
+        assert_eq!(
+            resolve(None, Some(2000), NO_JUMBO, V4),
+            mtu1500_shard_payload_for(V4)
+        );
     }
 
     #[test]
     fn env_full_mtu_is_the_default_wire_both_families() {
-        assert_eq!(resolve(Some(1500), None, V4), mtu1500_shard_payload_for(V4));
-        assert_eq!(resolve(Some(1500), None, V6), mtu1500_shard_payload_for(V6));
+        assert_eq!(
+            resolve(Some(1500), None, NO_JUMBO, V4),
+            mtu1500_shard_payload_for(V4)
+        );
+        assert_eq!(
+            resolve(Some(1500), None, NO_JUMBO, V6),
+            mtu1500_shard_payload_for(V6)
+        );
+    }
+
+    /// The happy path, both families: 9000 − 28 (IPv4) − 64 = 8908, and 9000 − 48 − 64 = 8888.
+    #[test]
+    fn proven_and_reproven_path_starts_jumbo() {
+        assert_eq!(jumbo_session_start(proven_jumbo(), V4), Some(8908));
+        let mut v6 = proven_jumbo();
+        v6.live_udp_mtu = 8952;
+        v6.proven_udp_budget = Some(8952);
+        assert_eq!(jumbo_session_start(v6, V6), Some(8888));
+        // …and it is what `resolve` returns, ahead of the env branch that would clamp a
+        // >1500 `PUNKTFUNK_WIRE_MTU` back down to the family default.
+        assert_eq!(resolve(Some(9000), None, proven_jumbo(), V4), 8908);
+    }
+
+    /// THE guard: the laptop that proved jumbo on the wired LAN and came back on a 1500-MTU
+    /// link. The memory still says jumbo; the live connection says otherwise; the live one
+    /// wins, every time. This is what makes the grow as safe as the clamp.
+    #[test]
+    fn a_remembered_verdict_never_grows_without_a_live_reproof() {
+        let mut moved = proven_jumbo();
+        moved.live_udp_mtu = 1472; // a clean 1500-MTU path, freshly measured
+        assert_eq!(jumbo_session_start(moved, V4), None);
+        assert_eq!(
+            resolve(None, None, moved, V4),
+            mtu1500_shard_payload_for(V4)
+        );
+        // Not even one byte of headroom short of the sealed target is enough.
+        let mut nearly = proven_jumbo();
+        nearly.live_udp_mtu = 8971;
+        assert_eq!(jumbo_session_start(nearly, V4), None);
+    }
+
+    /// …and the mirror: a live-proven path with no prior verdict still starts at the default.
+    /// Both halves are required, so a single fluke on either side cannot seal a jumbo wire.
+    #[test]
+    fn a_live_proof_alone_does_not_grow() {
+        let mut first_ever = proven_jumbo();
+        first_ever.proven_udp_budget = None;
+        assert_eq!(jumbo_session_start(first_ever, V4), None);
+        let mut weak_memory = proven_jumbo();
+        weak_memory.proven_udp_budget = Some(1472);
+        assert_eq!(jumbo_session_start(weak_memory, V4), None);
+    }
+
+    /// The two memories are keyed differently (clamp: peer; verdict: route), so they can
+    /// disagree. When they do, the one that keeps datagrams small wins.
+    #[test]
+    fn a_constrained_path_clamp_vetoes_the_grow() {
+        let mut contradicted = proven_jumbo();
+        contradicted.clamped_udp_budget = Some(1280);
+        assert_eq!(jumbo_session_start(contradicted, V4), None);
+        // A clamp that is itself at or above the sealed target isn't contrary evidence.
+        let mut roomy = proven_jumbo();
+        roomy.clamped_udp_budget = Some(8972);
+        assert_eq!(jumbo_session_start(roomy, V4), Some(8908));
+    }
+
+    #[test]
+    fn without_the_operator_opt_in_nothing_grows() {
+        let mut no_optin = proven_jumbo();
+        no_optin.target_wire_mtu = None;
+        assert_eq!(jumbo_session_start(no_optin, V4), None);
+    }
+
+    /// A legacy client (no `Hello::max_shard_payload`) is never handed a geometry it did not
+    /// advertise, and a client whose ceiling lands under the family default is left alone
+    /// rather than being "grown" to something smaller.
+    #[test]
+    fn the_client_ceiling_is_binding() {
+        let mut legacy = proven_jumbo();
+        legacy.client_ceiling = 0;
+        assert_eq!(jumbo_session_start(legacy, V4), None);
+        let mut small = proven_jumbo();
+        small.client_ceiling = 1408;
+        assert_eq!(jumbo_session_start(small, V4), None);
+        // A ceiling between the default and the path target caps the grow — and the proof
+        // then only has to cover the SMALLER sealed size.
+        let mut capped = proven_jumbo();
+        capped.client_ceiling = 4000;
+        assert_eq!(jumbo_session_start(capped, V4), Some(4000));
+    }
+
+    /// Every shard payload the grow can produce is even (Leopard FEC splits shards in halves)
+    /// and fits the receive ceiling every client sizes its buffers from.
+    #[test]
+    fn grown_shards_stay_even_and_inside_the_receive_ceiling() {
+        for mtu in [2000usize, 4000, 4001, 9000, 9216, 64000] {
+            for peer in [V4, V6] {
+                let Some(t) = jumbo_target(Some(mtu), u16::MAX, peer) else {
+                    continue;
+                };
+                assert_eq!(t % 2, 0, "odd shard for mtu {mtu}");
+                assert!(t <= punktfunk_core::config::max_shard_payload());
+                assert!(t > mtu1500_shard_payload_for(peer));
+                assert!(
+                    sealed_datagram_bytes(t) <= punktfunk_core::packet::MAX_DATAGRAM_BYTES,
+                    "sealed datagram overflows the receive ceiling at mtu {mtu}"
+                );
+            }
+        }
+        // Below the family default there is nothing to grow to.
+        assert_eq!(jumbo_target(Some(1500), u16::MAX, V4), None);
+        assert_eq!(jumbo_target(None, u16::MAX, V4), None);
+    }
+
+    /// A path is a (local interface, peer) pair, not a peer: the same client reached over the
+    /// host's other NIC is a different route with a different MTU.
+    #[test]
+    fn the_verdict_key_separates_routes_to_the_same_peer() {
+        let over_10g = PathKey {
+            local: Some(IpAddr::V4(Ipv4Addr::new(10, 0, 0, 1))),
+            peer: V4,
+        };
+        let over_wifi = PathKey {
+            local: Some(IpAddr::V4(Ipv4Addr::new(192, 168, 1, 1))),
+            peer: V4,
+        };
+        assert_ne!(over_10g, over_wifi);
+        assert_ne!(
+            over_10g,
+            PathKey {
+                local: None,
+                peer: V4
+            }
+        );
     }
 }

crates/punktfunk-host/src/session_plan.rs

@@ -193,12 +193,29 @@ impl SessionPlan {
                 // Surface the trade loudly: this is the single biggest per-frame cost a 4:4:4
                 // session adds (full-res CPU readback + swscale RGB→YUV444P every frame), and
                 // it looks like an unexplained fps ceiling if you don't know it happened.
-                tracing::warn!(
-                    "4:4:4 session on the NVENC path without PUNKTFUNK_ZEROCOPY: zero-copy GPU \
-                     capture DISABLED — every frame is CPU RGB + swscale RGB→YUV444P; expect a \
-                     lower fps ceiling than 4:2:0 at this mode (set PUNKTFUNK_ZEROCOPY=1 for the \
-                     GPU 4:4:4 convert)"
-                );
+                //
+                // Name the SESSION's codec, not the backend the gate is named after. The gate
+                // keys on `linux_zero_copy_is_vaapi()`, which reads the host-global encoder pref
+                // — so a per-session PyroWave negotiation on an NVENC/auto host lands here and
+                // was told it was "on the NVENC path", which is false in every particular: the
+                // wavelet encoder never touches NVENC, never swscales to YUV444P, and what it
+                // actually loses is the raw-dmabuf passthrough its whole design assumes.
+                if self.codec == crate::encode::Codec::PyroWave {
+                    tracing::warn!(
+                        "4:4:4 PyroWave session with PUNKTFUNK_ZEROCOPY off: zero-copy GPU \
+                         capture DISABLED — the wavelet encoder loses its raw-dmabuf passthrough \
+                         and every frame becomes a full-resolution CPU readback plus an upload \
+                         into its own Vulkan device; expect a materially lower fps ceiling (set \
+                         PUNKTFUNK_ZEROCOPY=1 to restore the passthrough)"
+                    );
+                } else {
+                    tracing::warn!(
+                        "4:4:4 session on the NVENC path without PUNKTFUNK_ZEROCOPY: zero-copy \
+                         GPU capture DISABLED — every frame is CPU RGB + swscale RGB→YUV444P; \
+                         expect a lower fps ceiling than 4:2:0 at this mode (set \
+                         PUNKTFUNK_ZEROCOPY=1 for the GPU 4:4:4 convert)"
+                    );
+                }
             }
             gpu && !force_cpu_for_nvenc_444
         };

crates/punktfunk-host/src/spike.rs

@@ -48,6 +48,17 @@ pub struct Options {
     pub out: PathBuf,
     /// Also round-trip every AU through a `punktfunk_core` host→client loopback and verify.
     pub loopback: bool,
+    /// PyroWave datagram-aligned packetization at this shard payload
+    /// ([`Encoder::set_wire_chunking`], plan §4.4) — what a real session passes from its
+    /// negotiated `shard_payload`. `None` = the dense one-packet-per-AU shape.
+    ///
+    /// This is also the switch that makes the STREAMED-AU wire reachable from the spike: with
+    /// it set and `PUNKTFUNK_PYROWAVE_STREAMED_AU=1` armed, the encoder's `poll_chunk` hands the
+    /// AU out in window-aligned pieces and the loopback seals them through
+    /// `begin_streamed_frame_at`/`seal_streamed_chunk`/`seal_streamed_finish` — the same path a
+    /// `VIDEO_CAP_STREAMED_AU` client drives. Without it there is no way to exercise PW6 end to
+    /// end outside a real client session.
+    pub wire_chunk: Option<usize>,
 }
 
 pub fn run(opts: Options) -> Result<()> {
@@ -114,9 +125,21 @@ pub fn run(opts: Options) -> Result<()> {
                     refresh_hz: opts.fps,
                 })
                 .context("create virtual output")?;
+            // `resolve` is the shared GameStream/spike constructor and hard-codes `pyrowave: false`
+            // (GameStream never negotiates it). The spike DOES know its codec, and on Linux that
+            // flag is what puts the capture on the raw-dmabuf passthrough
+            // (`ZeroCopyPolicy::pyrowave_session`, set from the same comparison in
+            // `session_plan::output_format`). Left false, `--codec pyrowave` encoded PyroWave off a
+            // capture negotiated for somebody else, and the only way to exercise the real path was
+            // the host-global `PUNKTFUNK_ENCODER=pyrowave` lever — which ALSO flips
+            // `backend_is_vaapi`, so it cannot reproduce a per-session PyroWave negotiation on an
+            // auto/NVENC host at all. That is precisely the configuration PW2 exists for.
+            let mut want =
+                capture::OutputFormat::resolve(false, crate::encode::resolved_backend_is_gpu());
+            want.pyrowave = opts.codec == Codec::PyroWave;
             capture::capture_virtual_output(
                 vout,
-                capture::OutputFormat::resolve(false, crate::encode::resolved_backend_is_gpu()),
+                want,
                 crate::session_plan::CaptureBackend::resolve(),
                 compositor == crate::vdisplay::Compositor::Kwin,
             )
@@ -155,6 +178,18 @@ pub fn run(opts: Options) -> Result<()> {
     )
     .context("open encoder")?;
 
+    // Datagram-aligned packetization (§4.4) — and, with the PW6 knob armed, the gate that makes
+    // `supports_chunked_poll()` true so the drain below takes the streamed-AU path.
+    if let Some(c) = opts.wire_chunk {
+        encoder.set_wire_chunking(c);
+        tracing::info!(
+            shard_payload = c,
+            chunked_poll = encoder.supports_chunked_poll(),
+            "spike: wire chunking on (chunked_poll=false means PUNKTFUNK_PYROWAVE_STREAMED_AU \
+             is not armed — the AU still goes out whole)"
+        );
+    }
+
     let mut sink = BufWriter::new(
         File::create(&opts.out).with_context(|| format!("create {}", opts.out.display()))?,
     );
@@ -194,6 +229,12 @@ pub fn run(opts: Options) -> Result<()> {
         out = %opts.out.display(),
         elapsed_s = format!("{elapsed:.2}"),
         encode_fps = format!("{:.1}", stats.encoded as f64 / elapsed.max(1e-9)),
+        // 0 = the whole-AU drain; > encoded = the streamed drain actually cut AUs into pieces.
+        chunks = stats.chunks,
+        chunks_per_au = format!(
+            "{:.1}",
+            stats.chunks as f64 / (stats.encoded.max(1)) as f64
+        ),
         "spike capture→encode→file complete"
     );
 
@@ -217,6 +258,9 @@ struct Stats {
     encoded: u64,
     keyframes: u64,
     bytes_out: u64,
+    /// Streamed-AU drain only: total chunks polled across all AUs (1 per AU means the cut never
+    /// engaged — the knob is off or the AU fits one chunk).
+    chunks: u64,
 }
 
 fn drain_encoder(
@@ -225,6 +269,12 @@ fn drain_encoder(
     mut lb: Option<&mut Loopback>,
     stats: &mut Stats,
 ) -> Result<()> {
+    // Streamed-AU drain (PW6): the encoder hands the finished AU out in shard-aligned pieces and
+    // the loopback seals each piece as it arrives, exactly as the native host's send thread does.
+    // Re-queried per drain, never cached — the trait's contract.
+    if encoder.supports_chunked_poll() {
+        return drain_encoder_chunked(encoder, sink, lb, stats);
+    }
     while let Some(au) = encoder.poll().context("encoder poll")? {
         sink.write_all(&au.data).context("write AU to file")?;
         stats.encoded += 1;
@@ -239,6 +289,49 @@ fn drain_encoder(
     Ok(())
 }
 
+/// The streamed-AU drain. Each chunk is sealed into the open wire frame the moment it is polled;
+/// the concatenation is kept only so the completed AU can still be written to the file sink and
+/// byte-compared against what the client reassembled — which is the point of the leg: it proves
+/// the chunks the encoder cut, sealed through the sentinel-block wire, reassemble to EXACTLY the
+/// AU `poll()` would have produced.
+fn drain_encoder_chunked(
+    encoder: &mut dyn Encoder,
+    sink: &mut impl Write,
+    mut lb: Option<&mut Loopback>,
+    stats: &mut Stats,
+) -> Result<()> {
+    let mut whole: Vec<u8> = Vec::new();
+    let mut chunks = 0u32;
+    while let Some(c) = encoder.poll_chunk().context("encoder poll_chunk")? {
+        if c.first {
+            whole.clear();
+            chunks = 0;
+            if let Some(lb) = lb.as_deref_mut() {
+                lb.streamed_begin(c.pts_ns, c.keyframe)?;
+            }
+        }
+        whole.extend_from_slice(&c.data);
+        chunks += 1;
+        if let Some(lb) = lb.as_deref_mut() {
+            lb.streamed_chunk(&c.data)?;
+        }
+        if !c.last {
+            continue;
+        }
+        sink.write_all(&whole).context("write AU to file")?;
+        stats.encoded += 1;
+        stats.bytes_out += whole.len() as u64;
+        stats.chunks += chunks as u64;
+        if c.keyframe {
+            stats.keyframes += 1;
+        }
+        if let Some(lb) = lb.as_deref_mut() {
+            lb.streamed_finish(&whole)?;
+        }
+    }
+    Ok(())
+}
+
 /// A host↔client `punktfunk_core` pair over a lossless in-process loopback. Each encoded AU is
 /// FEC-protected, packetized, sent, then reassembled on the client and byte-compared to the
 /// original — exercising the core on real encoder output (the spike "feed into a Session" goal).
@@ -249,6 +342,14 @@ struct Loopback {
     recovered: u64,
     mismatches: u64,
     bytes: u64,
+    /// The streamed AU currently open (PW6). `Some` strictly between `streamed_begin` and
+    /// `streamed_finish`, mirroring the native send thread's `StreamedOpen`.
+    open: Option<punktfunk_core::packet::StreamedAu>,
+    /// Wire frame index for the streamed path. `submit_frame` uses the packetizer's internal
+    /// counter and `begin_streamed_frame_at` takes an explicit one; a session must use ONE
+    /// numbering style, and the spike never mixes them (`supports_chunked_poll()` is constant
+    /// for a PyroWave session, so every AU takes the same route).
+    next_index: u32,
 }
 
 impl Loopback {
@@ -265,9 +366,101 @@ impl Loopback {
             recovered: 0,
             mismatches: 0,
             bytes: 0,
+            open: None,
+            next_index: 0,
         })
     }
 
+    /// Open a streamed AU on the wire (PW6). The client side needs no opt-in: a streamed frame
+    /// completes exactly like a whole one and is handed up as a single `Frame` — which is the
+    /// finding this leg exists to demonstrate rather than assert.
+    fn streamed_begin(&mut self, pts_ns: u64, keyframe: bool) -> Result<()> {
+        if self.open.is_some() {
+            return Err(anyhow!(
+                "streamed AU still open at begin — a previous AU never sent its `last` chunk"
+            ));
+        }
+        let mut flags = FLAG_PIC as u32;
+        if keyframe {
+            flags |= FLAG_SOF as u32;
+        }
+        let idx = self.next_index;
+        self.next_index = self.next_index.wrapping_add(1);
+        self.open = Some(
+            self.host
+                .begin_streamed_frame_at(pts_ns, flags, idx)
+                .map_err(|e| anyhow!("begin_streamed_frame_at: {e:?}"))?,
+        );
+        Ok(())
+    }
+
+    /// Seal + send one encoder chunk. The returned batch is often EMPTY (the sealer buffers
+    /// until a whole FEC block accumulates) — that is the normal case, not an error.
+    fn streamed_chunk(&mut self, data: &[u8]) -> Result<()> {
+        let au = self
+            .open
+            .as_mut()
+            .ok_or_else(|| anyhow!("streamed chunk with no open AU"))?;
+        let wires = self
+            .host
+            .seal_streamed_chunk(au, data, false)
+            .map_err(|e| anyhow!("seal_streamed_chunk: {e:?}"))?;
+        self.send(wires)
+    }
+
+    /// Close the AU (final block carries the real totals) and verify what the client got.
+    fn streamed_finish(&mut self, expect: &[u8]) -> Result<()> {
+        let au = self
+            .open
+            .take()
+            .ok_or_else(|| anyhow!("streamed finish with no open AU"))?;
+        let wires = self
+            .host
+            .seal_streamed_finish(au)
+            .map_err(|e| anyhow!("seal_streamed_finish: {e:?}"))?;
+        self.send(wires)?;
+        self.submitted += 1;
+        self.bytes += expect.len() as u64;
+        self.verify(expect)
+    }
+
+    fn send(&mut self, wires: Vec<Vec<u8>>) -> Result<()> {
+        if wires.is_empty() {
+            return Ok(());
+        }
+        let refs: Vec<&[u8]> = wires.iter().map(|w| w.as_slice()).collect();
+        self.host
+            .send_sealed(&refs)
+            .map_err(|e| anyhow!("send_sealed: {e:?}"))?;
+        drop(refs);
+        self.host.reclaim_wires(wires);
+        Ok(())
+    }
+
+    /// Drain whatever the client can now reassemble and byte-compare it to `expect`.
+    fn verify(&mut self, expect: &[u8]) -> Result<()> {
+        loop {
+            match self.client.poll_frame() {
+                Ok(frame) => {
+                    self.recovered += 1;
+                    if frame.data != expect {
+                        self.mismatches += 1;
+                        tracing::warn!(
+                            recovered = self.recovered,
+                            got = frame.data.len(),
+                            expected = expect.len(),
+                            complete = frame.complete,
+                            "loopback AU mismatch"
+                        );
+                    }
+                }
+                Err(punktfunk_core::PunktfunkError::NoFrame) => break,
+                Err(e) => return Err(anyhow!("client poll_frame: {e:?}")),
+            }
+        }
+        Ok(())
+    }
+
     fn submit(&mut self, au: &EncodedFrame) -> Result<()> {
         let mut flags = FLAG_PIC as u32;
         if au.keyframe {

crates/pyrowave-sys/patches/0005-global-priority-queue.patch

@@ -17,7 +17,38 @@ VK_ERROR_NOT_PERMITTED_KHR so a refused class NEVER regresses the encoder. Gated
 NOTE: on an RTX 4090 / Windows / WDDM this did not reduce the spikes (the graphics-vs-compute
 preemption granularity is the wall) — kept because it is correct, harmless (graceful fallback), and
 may help other GPUs/drivers. Reduce the encode's GPU cost (4:2:0/8-bit) or use H.265 for a
-GPU-saturated game.
+GPU-saturated game. **That measurement is Windows/WDDM and does NOT transfer to Linux** — a
+different driver stack with a different preemption model.
+
+MEASURED ON LINUX/NVIDIA 2026-08-08, and it comes out the OTHER WAY: the elevated queue DOES cut
+the tail. RTX 5070 Ti (driver 610.57.04), GRID 2 benchmark loop saturating the GPU at 54-87 %,
+PyroWave 1080p, same binary in both arms (the only difference is CAP_SYS_NICE, i.e. whether the
+class is granted at all), steady-state windows of 30 frames:
+
+  arm                       p50        p99        worst frame
+  default priority (refused) ~2.6 ms   ~6.4 ms    9.5 ms
+  REALTIME granted           ~3.2 ms   ~4.4 ms    5.4 ms      (repeat: p50 ~3.35, p99 ~4.8)
+
+So on this stack the priority class buys a materially tighter TAIL — p99 down ~30 %, worst frame
+roughly halved — at the cost of ~0.6 ms on the median. For a streaming encoder that is the right
+side of the trade: the tail is what shows up as a visible hitch. Do NOT delete this patch on the
+strength of the RTX 4090/WDDM result above; the two stacks disagree.
+
+Caveats, so the number is not over-read: the arms were not interleaved and the background game
+load drifted between them, capture was frame-starved (~2.5 fps) so this measures encode latency
+under contention rather than a full-rate stream, and it is two granted runs against one refused
+run. The direction was consistent across all 25 measurement windows.
+
+NOTE 2 — WHERE THIS PATCH IS ACTUALLY LIVE. It is gated `if (!inherit_info)`, and only the WINDOWS
+path leaves `inherit_info` null: `crates/pf-encode/src/enc/windows/pyrowave.rs` calls
+`pyrowave_create_device_by_compat`, so Granite builds the device itself and this block runs.
+**On LINUX it has never done anything.** `crates/pf-encode/src/enc/linux/pyrowave.rs::open_inner`
+passes its own instance/device create-infos into `pyrowave_device_create_info`, Granite's
+`MyDeviceFactory::get_existing_create_info()` returns them, `create_device` takes the inherit
+branch, and the whole block above is skipped. The Linux request is therefore wired natively in
+**`crates/pf-encode/src/enc/linux/pyrowave.rs`** (search `queue_priority_candidates`), which
+implements the SAME env grammar and the SAME downgrade ladder so one knob means one thing on both
+platforms. If you change the grammar here, change it there in the same commit.
 
 diff --git a/crates/pyrowave-sys/vendor/pyrowave/Granite/vulkan/context.cpp b/crates/pyrowave-sys/vendor/pyrowave/Granite/vulkan/context.cpp
 index 5257fc33..479eeded 100644

crates/pyrowave-sys/patches/0007-encoder-sequence-override.patch

@@ -0,0 +1,123 @@
+Encoder wire-sequence override — PUNKTFUNK LOCAL PATCH.
+
+Not upstream. Exposes `Encoder::set_next_sequence(uint32_t)` (and a
+`pyrowave_encoder_set_next_sequence` C entry) so the caller can stamp the 3-bit wire sequence
+counter itself instead of relying on the encoder object's private one.
+
+WHY IT EXISTS. PyroWave's `Encoder` structurally cannot hold two frames in flight: `Encoder::Impl`
+owns ONE each of `wavelet_img_high_res`, `bucket_buffer`, `meta_buffer`, `block_stat_buffer`,
+`payload_data` and `quant_buffer`, and `Impl::encode` OPENS by discarding them — an image barrier
+with `VK_IMAGE_LAYOUT_UNDEFINED` as the old layout (a written promise nothing else is reading it)
+plus three `fill_buffer` clears. Two `encode()` calls recorded into two command buffers and
+submitted to the same queue have no execution dependency in Vulkan, so encode N+1's DWT would
+overwrite the bands and zero the RDO buckets while encode N's block packing still reads them.
+
+So overlapping frames means TWO encoder handles on one device, alternated — which is fine for
+every resource above, because each handle gets its own. It is NOT fine for `sequence_count`, which
+also lives on `Impl` and is stamped into every block header (pyrowave_encoder.cpp `packing_push`).
+Two alternating handles each count 1,2,3... independently, so the wire sees 1,1,2,2,3,3...
+
+That is silently fatal on the decode side. `pyrowave_decoder.cpp` computes
+`diff = (hdr.sequence - last_seq) & 0x7` and treats `restart = diff != 0`, so a REPEATED value
+reads as "more blocks of the same frame": `clear()` never runs, `decoded_frame_for_current_sequence`
+stays true, and every second frame is swallowed. The symptom is "it works, just at half rate, with
+occasional mixed-frame blocks" — the kind of failure that passes a smoke test. It would hit every
+client, since pf-client-core and the Apple Metal hand-port parse the same field.
+
+WHAT IT DOES. `set_next_sequence(seq)` stores `(seq - 1) & SequenceCountMask`, because
+`Impl::encode` pre-increments before stamping — the setter's contract is about the next ENCODE, not
+the next store. The Rust side keeps one monotonic counter across both handles and calls this before
+each encode, so the wire sequence increments by exactly 1 mod 8 regardless of which handle produced
+the frame.
+
+INERT WHEN UNUSED. Nothing calls it unless the caller does, so the single-handle paths — including
+the whole Windows backend — behave exactly as before. No `.def` change is needed: the C API is
+built as a static archive (crates/pyrowave-sys/CMakeLists.txt).
+
+Upstream status: not reported. It is a hook for a use case upstream explicitly designed against
+("For low-latency use cases, overlapping frames in encode is meaningless due to latency and the
+encoder is so fast anyway" — pyrowave.h). That reasoning holds at 1080p60 and stops holding at 4K
+or under a GPU-bound game, which is what PW5 measured.
+
+diff --git a/crates/pyrowave-sys/vendor/pyrowave/pyrowave.h b/crates/pyrowave-sys/vendor/pyrowave/pyrowave.h
+index fc0d5834..aeb22ffc 100644
+--- a/crates/pyrowave-sys/vendor/pyrowave/pyrowave.h
++++ b/crates/pyrowave-sys/vendor/pyrowave/pyrowave.h
+@@ -476,6 +476,19 @@ PYROWAVE_PUBLIC_API pyrowave_result
+ pyrowave_encoder_packetize(pyrowave_encoder encoder, pyrowave_packet *packets, size_t packet_boundary,
+                            size_t *out_packets, void *bitstream, size_t size);
+ 
++// PUNKTFUNK LOCAL EXTENSION (patches/0007-encoder-sequence-override.patch), not upstream.
++// The wire sequence counter is 3 bits (PyroWave::SequenceCountMask, pyrowave_common.hpp);
++// exported here so callers mask with the codec's own value instead of a copied literal.
++#define PYROWAVE_SEQUENCE_MASK 0x7u
++
++// Overrides the 3-bit wire sequence counter the NEXT encode will stamp into every block header.
++// The counter lives on the encoder object, so a caller that alternates TWO encoders to overlap
++// frames emits 1,1,2,2,3,3... and the decoder — which restarts a frame only when the value
++// CHANGES — reads the repeat as more blocks of the same frame and silently swallows every second
++// frame. Stamp a single monotonic counter across the handles with this. Value is masked to 3 bits.
++PYROWAVE_PUBLIC_API pyrowave_result
++pyrowave_encoder_set_next_sequence(pyrowave_encoder encoder, uint32_t sequence);
++
+ // Implementation ensures GPU is idle before destroying objects.
+ PYROWAVE_PUBLIC_API void
+ pyrowave_encoder_destroy(pyrowave_encoder encoder);
+diff --git a/crates/pyrowave-sys/vendor/pyrowave/pyrowave_c.cpp b/crates/pyrowave-sys/vendor/pyrowave/pyrowave_c.cpp
+index 985cd0a9..fcd7d6f8 100644
+--- a/crates/pyrowave-sys/vendor/pyrowave/pyrowave_c.cpp
++++ b/crates/pyrowave-sys/vendor/pyrowave/pyrowave_c.cpp
+@@ -1196,6 +1196,17 @@ pyrowave_encoder_packetize(pyrowave_encoder encoder, pyrowave_packet *packets, s
+ 	return PYROWAVE_SUCCESS;
+ }
+ 
++// PUNKTFUNK LOCAL EXTENSION (patches/0007-encoder-sequence-override.patch), not upstream.
++pyrowave_result
++pyrowave_encoder_set_next_sequence(pyrowave_encoder encoder, uint32_t sequence)
++{
++	Util::set_thread_logging_interface(&null_logger);
++	if (!encoder)
++		return PYROWAVE_ERROR_GENERIC;
++	encoder->encoder.set_next_sequence(sequence);
++	return PYROWAVE_SUCCESS;
++}
++
+ void pyrowave_encoder_destroy(pyrowave_encoder encoder)
+ {
+ 	auto *device = encoder->device;
+diff --git a/crates/pyrowave-sys/vendor/pyrowave/pyrowave_encoder.cpp b/crates/pyrowave-sys/vendor/pyrowave/pyrowave_encoder.cpp
+index ad4e9746..f23717f3 100644
+--- a/crates/pyrowave-sys/vendor/pyrowave/pyrowave_encoder.cpp
++++ b/crates/pyrowave-sys/vendor/pyrowave/pyrowave_encoder.cpp
+@@ -1230,6 +1230,14 @@ bool Encoder::encode(CommandBuffer &cmd, const ViewBuffers &views, const Bitstre
+ 	return impl->encode(cmd, views, buffers);
+ }
+ 
++// PUNKTFUNK: see the declaration in pyrowave_encoder.hpp. Impl::encode PRE-increments
++// (sequence_count = (sequence_count + 1) & mask before stamping), so store one less than the value
++// the caller wants stamped — the setter's contract is about the next ENCODE, not the next store.
++void Encoder::set_next_sequence(uint32_t sequence)
++{
++	impl->sequence_count = (sequence - 1) & SequenceCountMask;
++}
++
+ const Vulkan::ImageView &Encoder::get_wavelet_band(int component, int level)
+ {
+ 	return *impl->component_layer_views[component][level];
+diff --git a/crates/pyrowave-sys/vendor/pyrowave/pyrowave_encoder.hpp b/crates/pyrowave-sys/vendor/pyrowave/pyrowave_encoder.hpp
+index a65447d5..8c0ef0d0 100644
+--- a/crates/pyrowave-sys/vendor/pyrowave/pyrowave_encoder.hpp
++++ b/crates/pyrowave-sys/vendor/pyrowave/pyrowave_encoder.hpp
+@@ -37,6 +37,12 @@ public:
+ 	bool init(Vulkan::Device *device, int width, int height, ChromaSubsampling chroma);
+ 	bool encode(Vulkan::CommandBuffer &cmd, const ViewBuffers &views, const BitstreamBuffers &buffers);
+ 
++	// PUNKTFUNK: override the 3-bit wire sequence counter the NEXT encode will stamp.
++	// The counter is per-Encoder, so alternating two encoder objects to overlap frames emits
++	// 1,1,2,2,3,3... and the decoder reads a repeated value as "more blocks of the same frame".
++	// See crates/pyrowave-sys/patches/0007-encoder-sequence-override.patch.
++	void set_next_sequence(uint32_t sequence);
++
+ 	// Debug hackery
+ 	const Vulkan::ImageView &get_wavelet_band(int component, int level);
+ 	bool encode_pre_transformed(Vulkan::CommandBuffer &cmd, const BitstreamBuffers &buffers, float quant_scale);

crates/pyrowave-sys/vendor/pyrowave/PUNKTFUNK-VENDOR.txt

@@ -46,4 +46,9 @@ upstream:
     realtime) so the wavelet encode can preempt a GPU-bound game on the shared shader cores. A
     create loop downgrades on NOT_PERMITTED so a refused class never regresses the encoder. Did
     not overcome the graphics-vs-compute preemption wall on an RTX 4090 (kept: correct + harmless,
-    may help other HW/drivers).
+    may help other HW/drivers) — that measurement is Windows/WDDM and does not transfer to Linux.
+    GATED ON !inherit_info, so it is LIVE ONLY ON THE WINDOWS PATH (pyrowave_create_device_by_compat,
+    where Granite builds its own device). Linux passes its own create-infos and takes the inherit
+    branch, so this patch is inert there; the Linux request lives natively in
+    crates/pf-encode/src/enc/linux/pyrowave.rs (queue_priority_candidates), with the same grammar
+    and the same downgrade ladder. Change one, change both.

crates/pyrowave-sys/vendor/pyrowave/pyrowave.h

@@ -476,6 +476,19 @@ PYROWAVE_PUBLIC_API pyrowave_result
 pyrowave_encoder_packetize(pyrowave_encoder encoder, pyrowave_packet *packets, size_t packet_boundary,
                            size_t *out_packets, void *bitstream, size_t size);
 
+// PUNKTFUNK LOCAL EXTENSION (patches/0007-encoder-sequence-override.patch), not upstream.
+// The wire sequence counter is 3 bits (PyroWave::SequenceCountMask, pyrowave_common.hpp);
+// exported here so callers mask with the codec's own value instead of a copied literal.
+#define PYROWAVE_SEQUENCE_MASK 0x7u
+
+// Overrides the 3-bit wire sequence counter the NEXT encode will stamp into every block header.
+// The counter lives on the encoder object, so a caller that alternates TWO encoders to overlap
+// frames emits 1,1,2,2,3,3... and the decoder — which restarts a frame only when the value
+// CHANGES — reads the repeat as more blocks of the same frame and silently swallows every second
+// frame. Stamp a single monotonic counter across the handles with this. Value is masked to 3 bits.
+PYROWAVE_PUBLIC_API pyrowave_result
+pyrowave_encoder_set_next_sequence(pyrowave_encoder encoder, uint32_t sequence);
+
 // Implementation ensures GPU is idle before destroying objects.
 PYROWAVE_PUBLIC_API void
 pyrowave_encoder_destroy(pyrowave_encoder encoder);

crates/pyrowave-sys/vendor/pyrowave/pyrowave_c.cpp

@@ -1196,6 +1196,17 @@ pyrowave_encoder_packetize(pyrowave_encoder encoder, pyrowave_packet *packets, s
 	return PYROWAVE_SUCCESS;
 }
 
+// PUNKTFUNK LOCAL EXTENSION (patches/0007-encoder-sequence-override.patch), not upstream.
+pyrowave_result
+pyrowave_encoder_set_next_sequence(pyrowave_encoder encoder, uint32_t sequence)
+{
+	Util::set_thread_logging_interface(&null_logger);
+	if (!encoder)
+		return PYROWAVE_ERROR_GENERIC;
+	encoder->encoder.set_next_sequence(sequence);
+	return PYROWAVE_SUCCESS;
+}
+
 void pyrowave_encoder_destroy(pyrowave_encoder encoder)
 {
 	auto *device = encoder->device;

crates/pyrowave-sys/vendor/pyrowave/pyrowave_encoder.cpp

@@ -1230,6 +1230,14 @@ bool Encoder::encode(CommandBuffer &cmd, const ViewBuffers &views, const Bitstre
 	return impl->encode(cmd, views, buffers);
 }
 
+// PUNKTFUNK: see the declaration in pyrowave_encoder.hpp. Impl::encode PRE-increments
+// (sequence_count = (sequence_count + 1) & mask before stamping), so store one less than the value
+// the caller wants stamped — the setter's contract is about the next ENCODE, not the next store.
+void Encoder::set_next_sequence(uint32_t sequence)
+{
+	impl->sequence_count = (sequence - 1) & SequenceCountMask;
+}
+
 const Vulkan::ImageView &Encoder::get_wavelet_band(int component, int level)
 {
 	return *impl->component_layer_views[component][level];