# 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.