> I suggest that we use fbdev (maybe at runtime, but maybe just disable everything
> else :P).

Selecting it at runtime should work well.

I've read kmscon source now and they wait for udev events in order to choose backends.

Once an udev event arrives, they check the result of udev_device_get_subsystem().
If it's "drm", they'll use [drm3d or] drm2d.
If it's "graphics", they'll use fbdev.

So it supports fbdev just fine and will select it when drm is unavailable.

(Note that on ARM, drm is required, otherwise you won't have video.  VESA
BIOS setup doesn't exist there--and never did)