https://bugs.freedesktop.org/show_bug.cgi?id=28016
--- Comment #2 from Grzegorz Kowal astronomo@op.pl 2010-05-07 04:48:35 PDT --- To be more precise, I bisected the commit introducing the problem. It is 6b8b1786a8c29ce6e32298b93ac8d4a18a2b11c4 (drm/radeon/kms: enable use of unmappable VRAM V2). Before it everything works fine.