drm/amdgpu: check ring being ready before using

Return success when the ring is properly initialized, otherwise return
failure.

Tonga SRIOV VF doesn't have UVD and VCE engines, the initialization of
these IPs is bypassed. The system crashes if application submit IB to
their rings which are not ready to use. It could be a common issue if
IP having ring buffer is disabled for some reason on specific ASIC, so
it should check the ring being ready to use.

Bug: amdgpu_test crashes system on Tonga VF.

Signed-off-by: Ding Pixel <Pixel.Ding@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 29d6d84d1c28b1e847715c08b6fac8f9d2a9aac3..41e41f90265df07af3299f65022feaf731e99ce7 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -83,6 +83,13 @@ int amdgpu_cs_get_ring(struct amdgpu_device *adev, u32 ip_type,
                }
                break;
        }
+
+       if (!(*out_ring && (*out_ring)->adev)) {
+               DRM_ERROR("Ring %d is not initialized on IP %d\n",
+                         ring, ip_type);
+               return -EINVAL;
+       }
+
        return 0;
 }