The host-lifetime libei injector could connect to a gamescope EIS socket whose
listen socket exists but whose server never drives the EI handshake — a stale
socket left by a SIGKILLed prior session, or one created early in a new
gamescope's startup before its libei server is ready. `UnixStream::connect` to a
socket *file* succeeds the moment the path exists, so the worker sailed past the
connect and then hung forever in `handshake_tokio` (or sat connected with no
device ever resumed). Because `LibeiInjector::inject` only enqueues onto a
channel (the !Send worker owns the connection), the send never errors, so
InjectorService never noticed the dead worker and never reopened — every input
event for the whole session was silently swallowed. The 30s setup timeout didn't
help: a typical session ends first, so input just died with no error logged.
Reconnecting made it worse (more stale sockets to land on).
Two self-heal bounds, both paths (gamescope socket + KWin/GNOME portal):
- Bound the EI handshake at 8s — a non-responding EIS server now errors instead
of hanging, so the worker exits and the next inject() reopens.
- Watchdog: if no input device resumes within 5s of connecting, treat the
connection as dead-on-arrival and exit (same reopen path). Healthy servers
add+resume a device within a beat of the handshake.
Verified on-box: clean gamescope + KWin paths connect/resume/emit unchanged; a
stale listener that accepts-but-never-handshakes now errors in 8s; two
back-to-back gamescope sessions both inject (session 2 reopens against the fresh
socket). Independently confirmed end-to-end delivery on KWin — a focused wev got
the injected motions/keys/buttons — i.e. injection itself was never broken, only
its recovery from a bad connection.
Also adds permanent low-volume diagnostics so the next "input dead" report is
instantly triageable: log each EIS device's capabilities on resume, the first of
each InputKind a client sends + whether it emitted, and no-resumed-device drops.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
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