Diagnosed live on the .181 Bazzite F44 box (couldn't connect at all; field
reports of streams dying after 30 s-5 min):
Bazzite autologs into game mode via SDDM with Relogin=true, so the moment the
managed takeover stops gamescope-session-plus@<client>, SDDM logs back in and
restarts it within the same second. The resurrected autologin session then
fights our transient session-plus over the Steam single instance and the GPU
for the whole stream: its wrapper relaunches gamescope every ~7 s (each one
missing the wrapper's hard 5 s readiness window on a slow NVIDIA init), the
churn SIGSEGVs gamescopes, and eventually the streaming gamescope dies with it.
Meanwhile a client that gave up left the pipeline-rebuild retry loop SIGKILLing
and relaunching the box's Steam session for up to ~6 more minutes.
- stop_autologin_sessions: runtime-mask each autologin unit before the SIGKILL
stop, so no supervisor can restart it underneath the stream; match every
loaded instance (the unit flaps through activating/failed mid-churn). Every
restore path unmasks unconditionally (including the desktop-active early
return), and --runtime keeps the mask in tmpfs so a reboot clears it.
- launch_session: supervise the transient unit while polling for the node —
the session-plus wrapper kill -9s a gamescope that missed its 5 s readiness
handshake and exits 1, so relaunch it (after a short driver-settle cooldown)
instead of waiting the rest of the 45 s on a corpse.
- build_pipeline_with_retry: abort between attempts once the session's QUIC
connection is closed — no more minutes of Steam churn for a departed client.
Validated live on .181: cold-boot connect streams 2059 frames/45 s (p50
5.1 ms), zero SDDM resurrections while masked, TV session restored+unmasked on
disconnect, warm same-mode reconnect reuses the session (866 frames/15 s).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
enricobuehler
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