[ Upstream commit 5e65c52ec7 ]
Loongson64 processors have a writecombine issue that maybe failed to
write back framebuffer used with ATI Radeon or AMD GPU at times, after
commit 8a08e50cee ("drm: Permit video-buffers writecombine mapping
for MIPS"), there exists some errors such as blurred screen and lockup,
and so on.
[ 60.958721] radeon 0000:03:00.0: ring 0 stalled for more than 10079msec
[ 60.965315] radeon 0000:03:00.0: GPU lockup (current fence id 0x0000000000000112 last fence id 0x000000000000011d on ring 0)
[ 60.976525] radeon 0000:03:00.0: ring 3 stalled for more than 10086msec
[ 60.983156] radeon 0000:03:00.0: GPU lockup (current fence id 0x0000000000000374 last fence id 0x00000000000003a8 on ring 3)
As discussed earlier [1], it might be better to disable writecombine
on the CPU detection side because the root cause is unknown now.
Actually, this patch is a temporary solution to just make it work well,
it is not a proper and final solution, I hope someone will have a better
solution to fix this issue in the future.
[1] https://lore.kernel.org/patchwork/patch/1285542/
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
8f7806174f