https://bugs.freedesktop.org/show_bug.cgi?id=109340
--- Comment #3 from Rafał Miłecki zajec5@gmail.com --- This problem also occurs when using drm/drm branch drm-next (5.0.0-rc1) with: [PATCH v7 00/20] MST refcounting/atomic helpers cleanup on top of it.
The only difference I've noticed is xrandr complaining about MIT-MAGIC-COOKIE-1:
xrandr
Invalid MIT-MAGIC-COOKIE-1 keyxrandr: Output DisplayPort-0 is not disconnected but has no modes Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384 eDP connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 174mm 1920x1080 60.02*+ 40.00 1680x1050 60.02 1280x1024 60.02 1440x900 60.02 1280x800 60.02 1280x720 60.02 1024x768 60.02 800x600 60.02 640x480 60.02 DisplayPort-0 connected (normal left inverted right x axis y axis) DisplayPort-1 disconnected (normal left inverted right x axis y axis) DisplayPort-2 disconnected (normal left inverted right x axis y axis) DisplayPort-3 disconnected (normal left inverted right x axis y axis) DisplayPort-4 disconnected (normal left inverted right x axis y axis) DisplayPort-5 disconnected (normal left inverted right x axis y axis)