• Tiezhu Yang's avatar
    MIPS: Loongson64: Use _CACHE_UNCACHED instead of _CACHE_UNCACHED_ACCELERATED · 5e65c52e
    Tiezhu Yang authored
    Loongson64 processors have a writecombine issue that maybe failed to
    write back framebuffer used with ATI Radeon or AMD GPU at times, after
    commit 8a08e50c ("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: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
    Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
    5e65c52e
cpu-probe.c 54.5 KB