https://bugzilla.kernel.org/show_bug.cgi?id=60709
--- Comment #18 from Rafał Miłecki zajec5@gmail.com --- Fix posted: [FIX][PATCH] drm/radeon: fix WREG32_OR macro setting bits in a register http://lists.freedesktop.org/archives/dri-devel/2013-August/043835.html