The recent rewrite of modesetting driver broke the 24bpp support.
As typically found on cirrus KMS, it leads to a blank screen, spewing
the error like:
failed to add fb -22
(EE) modeset(0): failed to set mode: Invalid argument
The culript is that the wrong bpp value of the front buffer is passed
to drmModeAddFB(). Fix it by replacing with the back buffer bpp,
drmmode->kbpp.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Stefan Dirsch <sndirsch@suse.de>
Reviewed-by: Adam Jackson <ajax@redhat.com>