For the record: mismatched nouveau and drm modules there's a drm module coming with your kernel too. on my system, I have: /lib/modules/2.6.29-2-amd64/char/drm/drm.ko /lib/modules/2.6.29-2-amd64/kernel/drivers/gpu/drm/drm.ko switching to the other module, workaround the issue.