First on-glass test of the DM-flavor takeover confirmed the black-screen
fix, but exposed that the managed model could not switch back: Steam's
in-stream session-select is a silent no-op while the display manager is
stopped (every config-write branch in os-session-select requires the DM
to be running), so the capture loss it causes just relaunched game mode.
The user pass of the switch script does leave one durable trace — the
~/.config/steamos-session-select sentinel, written before any DM check.
The managed launch now baselines its mtime; a capture loss with the
sentinel advanced reads as the switch request and is honored by
replaying the switch with the DM up: restore the display manager, run
the distro's own os-session-select (its internal pkexec is authorized
allow_any by the distro policy, so it works from the host's sessionless
context), then stop the autologin game-mode unit so Relogin lands in
the newly selected desktop. The capture-loss re-detection then follows
KWin as it comes up; a 120 s post-honor grace stops the rebuild loop
from racing the booting desktop back into game mode (superseded early
if the box's own game-mode unit reappears — the desktop→game leg stays
fast). The baseline is re-recorded on crash-restore so a pre-existing
sentinel never reads as a fresh request. Every verb in the sequence was
live-validated on the Nobara repro VM.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Field report (Nobara 43 HTPC): switching the host to Steam Game Mode
mid-stream permanently black-screened the box. Live-proven root cause on
a Nobara repro VM: our takeover masks the box's gamescope-session-plus
unit, plasmalogin's Relogin=true then fails its session Exec repeatedly
and trips systemd's start limit within ~1 s — the display manager dies,
and our restore verb (unmask + user start) cannot bring a seatless
gamescope back. Only 'reset-failed + restart' of the DM recovers.
The takeover is now display-manager-flavor-aware:
- SDDM (Bazzite/SteamOS) keeps the proven mask+SIGKILL path unchanged.
- plasmalogin/unknown DMs never mask: with privilege (root or an
operator polkit rule scoped to the DM unit — documented) the host
stops the DM for the stream and restores it with reset-failed +
restart (PUNKTFUNK_RECOVER_SESSION_CMD as fallback), recorded in the
persisted takeover state so a host crash still restores; without
privilege the managed takeover degrades to ATTACH and mirrors the
box's live Game Mode instead of destabilizing the seat. Both legs of
the privileged cycle live-verified on the repro VM (headless managed
session works with zero login sessions; render nodes are 0666).
A loaded-but-inactive leftover instance never triggers the DM stop.
Companion fixes from the same triage:
- ensure_box_gamescope_mode gains the attach-only rebuild-probe guard
both managed paths already had (stale post-capture-loss detection
restarted the box's unit), and no longer re-modes a box that drives a
physical display — attach mirrors on-glass; re-mode is the
headless-box model.
- Capture-loss rebuilds targeting gamescope get a 100 s budget: the
40 s budget expired inside the first 45 s Steam-cold-start launch
attempt, a guaranteed single-shot failure.
- A PUNKTFUNK_COMPOSITOR pin now WARNs once per capture loss when the
live session no longer matches it (the pin disables
session-following — the reporter's original stream-death trigger).
- A managed session that took nothing over (client gamescope pin beside
a live desktop) is stopped on disconnect instead of being orphaned
forever.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Field triage (Nobara, Discord): the kde.md starter host.env told desktop
users to set PUNKTFUNK_COMPOSITOR=kwin, which PINS the backend — detect()
short-circuits and the capture-loss rebuild never re-detects — so a
mid-stream switch to Game Mode killed the stream instead of following it.
A follow-up hardcoded XDG_RUNTIME_DIR=/run/user/1000 anchor broke PipeWire
for any non-1000 uid (pw audio connect: Creation failed).
Revamp across every starter/example/reference:
- Desktop starters (kde/gnome/hyprland/sway) shrink to
PUNKTFUNK_VIDEO_SOURCE=virtual + an explicit warning that pinning
disables session-following; forcing a backend is CI/appliance-only.
- host.env.example: rewritten around auto-detection; anchors demoted to a
commented ssh/cron-only block with the uid trap spelled out; the
gamescope ATTACH/MANAGED knobs documented (previously missing);
case-sensitivity called out.
- packaging/bazzite/host.env + README: drop the uid-1000 anchors (a
systemctl --user service inherits/derives them); README's stale
PUNKTFUNK_COMPOSITOR=gamescope-era template synced to the real one.
- packaging/kde/host.env: loud APPLIANCE-ONLY header (it pins on purpose).
- configuration.md: session-anchors section inverted to "leave unset",
compositor row states the pin consequence, case-sensitivity note.
- troubleshooting.md: new "session fails right after editing host.env"
section (case, wrong-uid anchors, stale pin, restart-to-apply).
- gamescope.md/bazzite.md: attach/managed descriptions match current
behavior (managed is the infra-detected default; attach re-modes a
box-owned session to the client's resolution).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
- rebuild-check.sh + punktfunk-rebuild-check.service (enabled, ordered
Before=punktfunk-host): ldd-probes the host binary at session start —
milliseconds when healthy, a full update.sh rebuild only when a
SteamOS update actually broke its library links. update.sh restarts
go --no-block so the check → update.sh → restart chain can't deadlock
against the unit ordering. update.sh retrofits the unit.
- installer summary: web console is https (the unit serves TLS).
- docs: steamos-host.md (runner in the build step, keep-list + auto
rebuild = updates survive hands-free), gamescope.md (Gaming Mode
touch = single-finger pointer, exact taps, no multi-touch),
plugins.mdx (SteamOS runner note), scripts/steamdeck/README.md
(rebuild-check, runner payload, keep list, honest packaging
trade-off + the CI-prebuilt future direction).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Split the docs' single distro×desktop axis (ubuntu-gnome / ubuntu-kde / fedora-kde) into two,
which deduplicates the shared mechanics and scales to distros that run several desktops (Arch):
- Install the host — per distro/OS (ubuntu, fedora, arch, bazzite, steamos-host, windows-host):
GPU driver + package + input group, then a canonical "Configure your desktop" funnel.
- Configure your desktop — per compositor (kde, gnome, gamescope, sway): host.env, compositor
quirks, the headless session, and starting the host.
New shared web-console page (enable · login password · arm pairing) removes the console/password
block that was copy-pasted across all seven host pages. Merged ubuntu-gnome + ubuntu-kde into
ubuntu; renamed fedora-kde to fedora; kept bazzite and steamos-host as dedicated appliance guides
(trimmed of duplication). Moved the KWin headless session, the GNOME EGL/lock traps, and the
gamescope attach/managed model out of the distro pages onto their compositor pages.
Fixed while restructuring: distro-specific paths on kde (kde-desktop-setup.sh is Fedora/Bazzite-only;
the .deb ships host.env.kde under /usr/share/punktfunk-host), the interactive "start the host" step
that was lost in the merge, sway over-claiming Hyprland, and a pre-existing broken anchor in
how-it-works.
Removal of the three old pages was captured by the preceding commit b28ddfc (a concurrent commit
swept up the staged git-rm); the net docs tree is correct. Fumadocs build + internal link/anchor
check green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehlerandClaude Fable 5