(In reply to comment #28)
> Using perf, I noticed it spent all of its
> time in a memcpy, and using gdb I found it was copying memory between
> textures in glamor.
With latest kernel 3.12.0, mesa 9.2.2 and ati 7.2 color corruption mostly
disappeared with the Native KDE backend and OpenGL 2.0 selected.

Although, every couple of seconds (every ~2-3 sec) my desktop lags for a
moment, using `perf top` I see:
 45.08%  [kernel]                 [k] radeon_vm_bo_set_addr 

which stays like that all the time. The desktop is pretty much usable, but
watching a HD movie is almost impossible with all that lagging every few
seconds.

> I'm using Gentoo with an HD7970.
Gentoo + HD7870 here.