Known bugs:
 - machine often hangs when starting directfb applications or starting
   xfree86 (using fbdev driver). however, once they started successfully,
   they run without problems. (misconfigured /etc/fb.modes?)
 - flat panel modes are not compared to bios values
 - mode switching for dfp is incomplete
 - 1bpp and 4bpp modes are unsupported
 - hardware cursor sucks - dead cursors remain on the screen in 16bpp,
   24bpp and 32bpp modes (disabled)
 - panning is broken under some conditions
