kiosk: no panel, no browser; start on hotplug, stop on unplug - #60
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petrus, 15 Sep 2026: the VTA's display had moved to the Pi and the kiosk kept drawing the dash for nobody: chrome + cage one full core, 80 C, fans, for four hours, measured by a pause test (46 C with the kiosk stopped, 76 C ninety seconds after restarting it; every DRM connector 'disconnected'). - carwatch-kiosk.sh checks /sys/class/drm/card*-*/status before starting and exits 78 when nothing is connected; while the browser runs it polls the panel every 5 s and stops the browser when it goes away. - carwatch-kiosk.service: RestartPreventExitStatus=78 / SuccessExitStatus=78, so a no-panel exit stays down instead of a 3 s restart loop. - 90-carwatch-kiosk.rules (udev, installed with the kiosk user substituted): a DRM hotplug event wants the service, so plugging the panel in starts it. - tests: fake DRM tree; no panel -> exit 78 and no browser; panel unplugged while running -> browser stopped, exit 78. Poll default 5 s (1 s in tests). Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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| # Start the CarWatch kiosk when a display is plugged in (DRM hotplug event). | |||
| # Installed by install-kiosk*.sh with the kiosk user substituted for KUSER. | |||
| SUBSYSTEM=="drm", ACTION=="change", ENV{HOTPLUG}=="1", TAG+="systemd", ENV{SYSTEMD_WANTS}+="carwatch-kiosk@KUSER.service" | |||
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After the kiosk exits on an unplug, the DRM device remains active and tagged, so reconnecting the same persistent connector produces another change event but no new device activation. The systemd.device(5) documentation states that SYSTEMD_WANTS dependencies are acted upon only when a device first becomes active; consequently, later reconnects will leave the kiosk stopped indefinitely. Toggle SYSTEMD_READY with the connection state or use a mechanism that explicitly starts the service on each connected hotplug.
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…al logging codexmb, #60 review: SYSTEMD_WANTS on a device unit fires once when the device becomes active; card0 stays active across unplug/replug, so the kiosk would not restart on the next plug. Now a udev RUN calls carwatch-kiosk-hotplug.sh, which reset-fails and starts the unit (--no-block). Measured on the VTA while getting there: a rule keyed on any DRM change event restarts the kiosk from its own start, because the VT switch of the start emits a change event too: 517 starts in a minute. ENV{HOTPLUG}=="1" is what separates a real plug (kernel drm_sysfs_hotplug_event) from that; with it, three synthetic triggers plus a manual start produced exactly one start. The unit's start-rate limit is raised (a plug can be a burst) so a burst cannot leave the unit 'failed'. The launcher's no-panel and unplug messages now also go to the journal via logger, since stderr under a TTY-bound unit does not. Verified: 5/5 launcher tests; on the VTA: launcher exit 78 with no panel, rule listed by udevadm test, no feedback with the HOTPLUG guard. Not yet verified: a real plug event (needs the panel on the VTA). Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
…le; comments corrected codexmb, #59 review: Promise.race abandoned a still-running fn, so the test's never-settling first call was alive when the second started and proved nothing about overlap. Now each run gets an AbortController; poll, pollSteer and pollVoice pass its signal into F (which links an outer signal to its own abort timer); at CW_DEADLINE the signal is aborted and the run is awaited until it settles, bounded by CW_SETTLE_GRACE for a fn that ignores its signal. The test's stalled fn honours the signal like a real fetch and the harness asserts the order call1, settle1, call2 and settled == 1; the previous scheduler fails it (settled 0, overlapping calls). Comments corrected: the timers were request waste, not the VTA's 80 C (that was the kiosk drawing to no panel, #60); a hidden tab keeps the loop ticking and skips the fetch, it does not stop polling outright. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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petrus, 15 Sep 2026: the VTA's display had moved to the Pi and the kiosk kept drawing the dash for nobody: chrome + cage held one full core at 80 C for four hours. Pause test: 46 C with the kiosk stopped, 76 C ninety seconds after restarting it; every DRM connector reads
disconnected.carwatch-kiosk.sh: checks/sys/class/drm/card*-*/statusbefore starting and exits 78 when nothing is connected; while the browser runs it re-checks every 5 s (CARWATCH_PANEL_POLL) and stops the browser when the panel goes away.carwatch-kiosk.service:RestartPreventExitStatus=78+SuccessExitStatus=78, so a no-panel exit stays down instead of a 3 s restart loop.90-carwatch-kiosk.rules(udev, both installers substitute the kiosk user): a DRM hotplug event wants the service, so plugging a panel in starts it without anyone enabling anything.tests/test_kiosk_launcher.py, fake DRM tree): no panel -> exit 78 and no browser; panel unplugged mid-run -> browser stopped, exit 78; the three existing cases updated to declare a connected panel. 5/5 pass locally.Deploy note for the VTA: the kiosk service there is currently disabled by hand (17:47Z); after merge, re-run
scripts/kiosk/install-kiosk-ubuntu.shonce, which installs the rule and enables the unit, and it stays down until a panel appears.Review before merge welcome, @codexmb.
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