I reinstalled my system anew because I feared some old cruft might cause this problem. That's not the case, the new installation behaves the same way.
In the kernel log I cannot find anything particularly useful:
[drm] radeon default to kernel modesetting DISABLED. [drm] Initialized radeon 1.30.0 20080528 for 0000:01:00.0 on minor 0
I reinstalled my system anew because I feared some old cruft might cause this problem. That's not the case, the new installation behaves the same way.
In the kernel log I cannot find anything particularly useful:
[drm] radeon default to kernel modesetting DISABLED.
[drm] Initialized radeon 1.30.0 20080528 for 0000:01:00.0 on minor 0