drm/amdgpu: A workaround for JPEG_v4_0_3 ring test fail

The jpeg_v4_0_3 jpeg_pitch register uses UVD_JRBC_SCRATCH0. It needs to
move WREG() to after jpeg_start.
Switch to a posted register write when doing the ring test to make sure
the register write lands before we test the result.

Signed-off-by: Sonny Jiang <sonny.jiang@amd.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
index 388466a..9a1db2b 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
@@ -124,11 +124,14 @@ int amdgpu_jpeg_dec_ring_test_ring(struct amdgpu_ring *ring)
        if (amdgpu_sriov_vf(adev))
                return 0;
 
-       WREG32(adev->jpeg.inst[ring->me].external.jpeg_pitch[ring->pipe], 0xCAFEDEAD);
        r = amdgpu_ring_alloc(ring, 3);
        if (r)
                return r;
 
+       WREG32(adev->jpeg.inst[ring->me].external.jpeg_pitch[ring->pipe], 0xCAFEDEAD);
+       /* Add a read register to make sure the write register is executed. */
+       RREG32(adev->jpeg.inst[ring->me].external.jpeg_pitch[ring->pipe]);
+
        amdgpu_ring_write(ring, PACKET0(adev->jpeg.internal.jpeg_pitch[ring->pipe], 0));
        amdgpu_ring_write(ring, 0xDEADBEEF);
        amdgpu_ring_commit(ring);