This patch adds the missing code comment for memory barrier WARNING: memory barrier without comment + mb();
WARNING: memory barrier without comment + mb(); Cc: Guchun Chen <[email protected]> Cc: Christian König <[email protected]> Cc: Alex Deucher <[email protected]> Cc: "Pan, Xinhui" <[email protected]> Signed-off-by: Srinivasan Shanmugam <[email protected]> --- v4: - Incorporated comments from (Lijo) drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c index 4f818f13dc9d..65c36987f7d6 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -305,10 +305,16 @@ size_t amdgpu_device_aper_access(struct amdgpu_device *adev, loff_t pos, if (write) { memcpy_toio(addr, buf, count); + /* Make sure HDP write cache flush happens without any reordering + * after the system memory contents are sent over PCIe device + */ mb(); amdgpu_device_flush_hdp(adev, NULL); } else { amdgpu_device_invalidate_hdp(adev, NULL); + /* Make sure HDP read cache is invalidated before issuing a read + * to the PCIe device + */ mb(); memcpy_fromio(buf, addr, count); } -- 2.25.1
