drm/msm/adreno: fix updating ring fence

[ Upstream commit f228af11dfa1d1616bc67f3a4119ab77c36181f1 ]

We need to set it to the most recent completed fence, not the most
recent submitted.  Otherwise we have races where we think we can retire
submits that the GPU is not finished with, if the GPU doesn't manage to
overwrite the seqno before we look at it.

This can show up with hang recovery if one of the submits after the
crashing submit also hangs after it is replayed.

Fixes: f97decac5f4c ("drm/msm: Support multiple ringbuffers")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index 5db06b5909438fac5abe2f0c0195aadb152275ca..e7b39f3ca33dc3906cb0140f974bde97e2182ea7 100644 (file)
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -396,7 +396,7 @@ int adreno_hw_init(struct msm_gpu *gpu)
                ring->next = ring->start;
 
                /* reset completed fence seqno: */
-               ring->memptrs->fence = ring->seqno;
+               ring->memptrs->fence = ring->fctx->completed_fence;
                ring->memptrs->rptr = 0;
        }