https://bugs.freedesktop.org/show_bug.cgi?id=47765
--- Comment #8 from Tvrtko Ursulin tvrtko.ursulin@onelan.co.uk 2012-04-04 06:57:36 PDT --- (In reply to comment #7)
Does this patch help? http://people.freedesktop.org/~agd5f/0001-drm-radeon-kms-Fixup-backendmap-on...
Unfortunately not, still the same behaviour.