drm/amdgpu/{uvd,vcn}: fetch ring's read_ptr after alloc

[What]
readptr read always returns zero, since most likely
these blocks are either power or clock gated.

[How]
fetch rptr after amdgpu_ring_alloc() which informs
the power management code that the block is about to be
used and hence the gating is turned off.

Signed-off-by: Louis Li <Ching-shih.Li@amd.com>
Signed-off-by: Shirish S <shirish.s@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
index ecf6f96df2ad..e6b07ece3910 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
@@ -594,7 +594,7 @@ error:
 int amdgpu_vcn_enc_ring_test_ring(struct amdgpu_ring *ring)
 {
         struct amdgpu_device *adev = ring->adev;
-        uint32_t rptr = amdgpu_ring_get_rptr(ring);
+        uint32_t rptr;
         unsigned i;
         int r;
 
@@ -602,6 +602,8 @@ int amdgpu_vcn_enc_ring_test_ring(struct amdgpu_ring *ring)
         if (r)
                 return r;
 
+        rptr = amdgpu_ring_get_rptr(ring);
+
         amdgpu_ring_write(ring, VCN_ENC_CMD_END);
         amdgpu_ring_commit(ring);