enricobuehler
38cce754bd
Both landed in 3363576 and validated live on the Bazzite F44 box: a Gaming→Desktop
mid-stream switch shows `settled desktop portal env … compositor=kwin` →
`portal granted devices` → `device RESUMED` (input lands, no reconnect), and
`KWin: streamed output set as the sole desktop also_disabled=["HDMI-A-1"]` (panels
on the streamed screen). Remaining: #1 (F44 gamescope teardown GPU leak) + the
lower-priority polish.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
4.3 KiB
Session-aware host — known limitations & follow-ups
Status: 2026-06-14. The host auto-detects the live session (Gaming / KDE / GNOME / wlroots) per
connect and routes both video and input at it — managed gamescope at the client's resolution in
Steam Gaming Mode, a KWin/Mutter virtual output at the client's resolution on a Desktop. A watcher
(opt-in: PUNKTFUNK_SESSION_WATCH=1) follows a Gaming↔Desktop switch mid-stream and rebuilds the
backend in place without a reconnect.
Live-validated on the Bazzite F44 box (bazzite-deck-nvidia:testing, RTX 4090): Desktop KDE at
5120×1440 + input; Gaming managed at 5120×1440; warm-session reuse on quick reconnect; Feature B
video-switch both directions.
Resolved (2026-06-15, 3363576)
- #2 — mid-stream-switch input ✅
vdisplay::settle_desktop_portal()pushes the live session env into the systemd/D-Bus activation environment and restarts the KWin portal on a switch, so input lands without a reconnect. Validated live:settled desktop portal env … compositor=kwin→libei: portal granted devices→device RESUMEDon a Gaming→Desktop mid-stream switch. - #3 — KWin/Mutter virtual output primary ✅
apply_session_envdefaultsPUNKTFUNK_KWIN_VIRTUAL_PRIMARY/PUNKTFUNK_MUTTER_VIRTUAL_PRIMARYon for the auto desktop path. Validated live:KWin: streamed output set as the sole desktop also_disabled=["HDMI-A-1"]— panels now render on the streamed screen.
Still parked
1. F44 gamescope teardown corrupts the GPU context
Every gamescope teardown on this box (stop the autologin on connect; stop the managed session on
restore) risks leaking the NVIDIA GPU context — surfaces as CUDA_ERROR_ILLEGAL_STATE (401) in
cuCtxCreate / vkCreateDevice VK_ERROR_INITIALIZATION_FAILED (-3), then a black screen that
needs a reboot. The 5 s debounced restore + the desktop restore-guard cut the teardown count
but don't eliminate it. Options, in order of preference:
- SIGKILL the gamescope on teardown instead of
systemctl stop(SIGTERM). Hypothesis: skipping gamescope's buggy SIGTERM teardown handler (the part that SIGSEGVs, exit 139) lets the process die hard and the driver reclaim its GPU resources cleanly via normal process exit — no half-torn-down context. Changestop_autologin_sessions+stop_session(vdisplay/gamescope.rs) tosystemctl --user kill --signal=SIGKILL <unit>(+ a follow-upstop/reset-failedto clear unit state). Untested — this is the first thing to try; it would preserve "managed client-res gaming AND TV-shows-gaming-when-idle". - Keep the managed session warm (no per-disconnect restore): spawn once, reuse forever, never tear down → ~1 teardown per host lifetime. Tradeoff: the TV is blank/idle when no client is connected (the autologin is never restored; return to gaming manually).
- Upstream gamescope/driver fix.
(#2 mid-stream-switch input and #3 virtual-output-primary are resolved — see the Resolved section above.)
Lower priority / polish
4. Mid-stream-switch input loss window (~6 s)
During the libei portal setup on a switch, buffered input drops (libei: DROP — no resumed device,
hundreds of events). Polish: pre-warm the portal, or hold events instead of dropping during the
device-resume window.
5. NVENC InitializeEncoder failed: invalid param (recovered)
At 5120×1440@240 the first NVENC open fails with invalid param (8) and recovers via the 2-way
split-encode path (the stream is live). Cosmetic but noisy — investigate the first-attempt failure /
silence the log.
6. NVENC HEVC bitrate cap (~800 Mbps on the RTX 4090)
HEVC opens at the GPU's max (~800 Mbps) when a higher rate is requested (e.g. 1600). Not a bug; consider preferring AV1 when the client requests >~800 Mbps HEVC, and surface the cap in the speed-test / bitrate UI.
7. Restore-guard / keep-warm model interaction
do_restore_tv_session, when a desktop is active, still stops the idle managed gamescope (a teardown
— leak risk per #1) and consumes STOPPED_AUTOLOGIN (so a later return-to-gaming won't auto-restore
the TV session). Resolve together with the keep-warm decision in #1.
8. Feature B is opt-in
The mid-stream watcher is gated behind PUNKTFUNK_SESSION_WATCH=1 pending broader validation. Promote
to default-on once #2 (mid-stream input) lands and it's exercised on more boxes.