Comment # 8 on bug 1179387 from Felix Miata (offline until ???)

Without xf86-video-ati installed, Xorg.0.log reports using modeset(0), and
nothing beyond background graphic when Xorg is started. 'Driver "vesa"' in
xorg.con* results in "vesa: Ignoring device with a bound kernel driver",
followed by lots of (EE) lines, including no screens found(EE) and fatal server
error, when KMS is not disabled.

Booting with nomodeset, and vesa configured, #2 (EE) in log is "VESA(0): No
V_BIOS found", so X fails to run. Removing the vesa config (100% automagic
restored) allows the DM to open normally running FBDEV(0) @1024x768 on a
1680x1050 display.

ISTR modesetting DDX does not support Radeons as new as rv370 or so, so
wouldn't for rv250 here either.