The SteamOS scripts built the host featureless, so PlatformAuto could never
pick the Vulkan Video backend (default-on since 84329205) and every session
silently ran libav VAAPI — unlike the deb/arch/rpm/sysext builds, which all
pass the feature. Three gaps, found live on a Deck host:
- install.sh/update.sh: cargo build with --features punktfunk-host/vulkan-encode
(matches the packaged builds; pure-Rust ash, no new system dep).
- host.env: RADV_PERFTEST=video_encode — Van Gogh RADV still gates
VK_KHR_video_encode_* behind it, so without it the backend can't open and
falls back to VAAPI. Harmless where encode is exposed by default.
- io.unom.Punktfunk.Host.desktop (Exec rewritten to this install's binary):
KWin only grants zkde_screencast_unstable_v1/org_kde_kwin_fake_input to an
exe a .desktop authorizes — without it Desktop-Mode capture fails outright
and a mid-stream Game↔Desktop switch strands the stream on the old backend.
update.sh retrofits the last two idempotently so existing installs get them
without a reinstall.
Validated on a SteamOS 3.8.14 Deck (Van Gogh): Vulkan HEVC opened on both the
KWin and gamescope paths at 5120x1440 — in-place ABR reconfigure (no IDR, no
encoder rebuild) vs the VAAPI path's full teardown per ABR step, and Desktop
capture came up without a re-login.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SteamOS is immutable read-only Arch, and the Deck is AMD (VAAPI) — so none of the
checked-in packaging (arch/sysext is NVENC-first + client-oriented, deb/rpm are
soname-mismatched) actually installs a working host on a Steam Deck. The proven path
(distrobox-built native binary + systemd-run units) was 100% manual. Make it one command.
- scripts/steamdeck/install.sh — idempotent installer: ensure the pf2 Debian-trixie
distrobox + toolchain → build host (+web console) → write config (generated web login
password) → raise UDP buffers to 32 MB + udev + input group (sudo, skipped gracefully
if unavailable) → install + start punktfunk-host / punktfunk-web systemd USER services
with linger. Flags: --open (accept unpaired clients), --no-web, --src=DIR. Builds
on-device so a rebuild always matches the running SteamOS (no prebuilt-binary fragility
across OS updates); VAAPI on the Deck's AMD GPU.
- scripts/steamdeck/update.sh — rebuild from current source + restart (config/pairings persist).
- scripts/steamdeck/README.md — deep reference (why on-device, what's installed, gotchas).
- docs-site: new "Steam Deck (Host)" guide + sidebar entry; install.md splits Arch from the
Steam Deck host path; packaging/arch/README points Deck-host users here and corrects the
stale "NVENC-only" note (VAAPI host encode landed).
Live-validated on the Deck: installer runs clean, both services come up, host listens
(QUIC :9777 + mgmt :47990), web serves (302→login); on a client connect it takes over the
Game-Mode gamescope session at the client's mode, captures via PipeWire, and VAAPI-encodes
(hevc_vaapi) — full pipeline confirmed in the host journal.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehlerandClaude Opus 4.8