Screen orientation / auto-rotate on the PineTab2

Desktop
1

I have a PineTab2 tablet. When it is docked to the keyboard it is in fixed landscape mode, when it is undocked it can auto-rotate the screen based on the accellerometer.

Sadly this does not seem to quite work in GNOME:

  • When I configure ACCEL_MOUNT_MATRIX so that monitor-sensors considers the tablet ‘normal’ when the keyboard connector is at the bottom, when I disconnect the keyboard, the screen is auto-rotated to always rotated 90 degrees to the left.

  • When I configure ACCEL_MOUNT_MATRIX so that monitor-sensors considers the tablet ‘normal’ in portrait mode with the buttons on the top edge, the screen auto-rotates correctly, but now the screen is rotated 90 degrees when I connect the keyboard.

Is there any other setting to take into account to get this right? It seems to work on plasma.

2

Reading up on this more, I have some observations:

  • The ‘native’ orientation of this display panel is portrait (checked with /sys/class/drm/card0-DSI-1/modes)
  • The ‘native’ orientation of this tablet is landscape. libdrm knows about this (modetest confirms it is oriented ‘Right Side Up’, xrandr (under wayland) indeed shows the resolutions in landscape mode
  • ACCEL_MOUNT_MATRIX should be set so that monitor-sensors considers the orientation ‘normal’ when it is in the display panel’s ‘native’ orientation, i.e. portrait
  • When the tablet is docked, I can set Settings→Display→Orientation to ‘Landscape’ to orient the screen correctly
  • When the tablet is not docked, it indeed auto-rotates correctly (and Settings→Display→Orientation is not available)
  • When the tablet is docked again (PanelOrientationManaged become false again), Settings→Display→Orientation (incorrectly) appears as “Portrait Right” and the display is rotated.

I guess I want GNOME to remember the Settings→Display→Orientation setting even when it temporarily disappears when I undock the tablet. Would that make sense?

3

for now I ended up creating an udev rule that does gdctl set --logical-monitor --primary --monitor=DSI-1 --transform normal whenever USB device 1018:1006 appears. Note gdctl needs DBUS_SESSION_BUS_ADDRESS to be set.

For Nix users I shared my configuration for this device on codeberg

I’d be interested in contributing a fix that would make this work right out-of-the-box without udev, though, but it wasn’t clear to me where that should live.