HDMI unplug lights the panel: board run 2026-10-16

Change: the-display-lights-when-hdmi-is-unplugged. Evidence class: board journal and Sway IPC state. The operator handled the cable and pressed the power key, and reported “works” (the panel lit after the unplug). There was no camera recording.

Installed

The system was deployed live from commit 91a60bfb (first implementation, which woke the display on the relay’s Trackpad → DirectTouch edge): /nix/store/b6wn851s2005i1gm6r6pnxk72waajzl3-nixos-system-nixos-26.11.20260919.20b1ddd.

Journal (filtered, same boot)

13:36:10 kernel: canaan-mipi-dsi 90850000.dsi: HDMI HPD: connected
13:36:12 k230-touch-trackpad: mode -> Trackpad (panel connected: false)
13:36:29 kernel: k230-pmu-pwrkey: INT0 press / INT0 release
13:36:29 sway: Handling command 'output * power off'
13:36:30 k230-touch-trackpad: mode -> DirectTouch (panel connected: false)
13:36:30 sway: Handling command 'output * power on'
13:36:31 kernel: canaan-mipi-dsi 90850000.dsi: HDMI HPD: disconnected
13:36:31 sway: Handling command 'output * power on'
13:36:32 k230-touch-trackpad: mapped direct touch to DSI-1 and powered the display on

Afterwards, swaymsg -t get_outputs reported DSI-1 with "power": true.

What it shows

The unplug lit the panel with direct touch, as the operator reported.
It also exposed a flaw in that first implementation. The power-key blank at 13:36:29 disabled HDMI scanout with the cable still in. The relay then left trackpad mode at 13:36:30 and sent power on, one second before HPD reported the unplug. With the cable left in, that would have turned the monitor straight back on after every power-off.
Commit 28302fb3 makes the wake depend on the HDMI connector status changing from connected to not connected. Its board check is task 1.4.

Not shown

The short press after the wake that should darken the panel (task 1.3).
The corrected build on the board (task 1.4).

Corrected build: operator run at 14:04 (tasks 1.3 and 1.4)

The corrected system, from commit 28302fb3 (the relay wakes on the connector’s unplug), was deployed live: /nix/store/cmqgscqmbhgz9bgkxyi069a0i88nfbrr-nixos-system-nixos-26.11.20260919.20b1ddd.

The operator’s report: “hdmi power worked with hdmi, unplug made panel light up, power makes panel dark, power wakes it”.

Journal (filtered, same boot):

14:04:28 sway: Handling command 'output * power on'            (wake on HDMI)
14:04:28 k230-touch-trackpad: mode -> Trackpad (panel connected: false)
14:04:31 kernel: k230-pmu-pwrkey: INT0 release
14:04:31 sway: Handling command 'output * power off'           (monitor dark)
14:04:31 k230-touch-trackpad: mode -> DirectTouch (panel connected: false)
14:04:33 kernel: canaan-mipi-dsi 90850000.dsi: HDMI HPD: disconnected
14:04:34 sway: Handling command 'output * power on'
14:04:34 k230-touch-trackpad: mapped direct touch to DSI-1 and powered the display on
14:04:35 kernel: k230-pmu-pwrkey: INT0 release
14:04:35 sway: Handling command 'output * power off'           (panel dark)
14:04:36 kernel: k230-pmu-pwrkey: INT0 release
14:04:36 sway: Handling command 'output * power on'            (panel wakes)

Task 1.4. The power-off at 14:04:31 left the relay in direct touch, as before, but sent no wake while the cable stayed in. The monitor stayed dark, per the operator, until the unplug.
Task 1.3. The unplug lit the panel with direct touch one second after HPD. The next short press darkened it, because the daemon read Sway’s power: true instead of its own stale “dark”. A further press woke it.