24bpp front buffers tend to be the least well tested path for client
rendering. On the qemu cirrus emulation, and on some Matrox G200 server
chips, the hardware can't do 32bpp at all. It's better to just allocate
a 32bpp shadow and downconvert in the upload hook than expose a funky
pixmap format to clients.
[ajax: Ported from RHEL and separate modesetting driver, lifted kbpp
into the drmmode struct, cleaned up commit message, fixed 16bpp]
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Dave Airlied <airlied@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
[hdegoede@redhat.com: rebase, also use kbpp for rotate shadow fb]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
21217d0216