Comment 29 for bug 363238

http://dri.freedesktop.org/wiki/DriTroubleshooting

$ dmesg | egrep '(agp|drm)'
[ 10.438552] Linux agpgart interface v0.103
[ 12.069499] agpgart-intel 0000:00:00.0: Intel 830M Chipset
[ 12.085770] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xd0000000
[ 59.768684] [drm] Initialized drm 1.1.0 20060810
[ 59.934077] [drm] Initialized radeon 1.29.0 20080528 on minor 0

$ grep -i "Direct rendering" /var/log/Xorg.0.log
(WW) RADEON(0): Direct rendering disabled

$ grep EE /var/log/Xorg.0.log
 (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(II) Loading extension MIT-SCREEN-SAVER
(EE) RADEON(0): Static buffer allocation failed. Disabling DRI.
(EE) RADEON(0): At least 16735 kB of video memory needed at this resolution and depth.
(EE) AIGLX error: dlopen of /usr/lib/dri/swrast_dri.so failed (/usr/lib/dri/swrast_dri.so: cannot open shared object file: No such file or directory)
(EE) GLX: could not load software renderer
(EE) Generic Keyboard: No device specified.
(EE) PreInit returned NULL for "Generic Keyboard"
(EE) ioctl EVIOCGBIT failed: Inappropriate ioctl for device
(EE) PreInit returned NULL for "Configured Mouse"

-> adding Load "glx" to the modules section and retrying.