Created attachment 107655 [details] [review]
drm/radeon: Ignore RADEON_GEM_GTT_WC on Kabini

There seems to be a general problem with write-combined CPU mappings of GTT on
Kabini. We previously disabled write-combined mappings of the ring buffers
again because other users reported ring test failures on Kabini with that, but
from this report it looks like the problem runs deeper.

This kernel patch should work around it for now.