diff mbox series

[v3,2/3] drm/msm: Fix races managing the OOB state for timestamp vs timestamps.

Message ID 20210128210332.1690609-3-eric@anholt.net
State Accepted
Commit 5f98b33b04c02c0d9088c7486c59d058696782f9
Headers show
Series drm/msm: fix for "Timeout waiting for GMU OOB set GPU_SET: 0x0" | expand

Commit Message

Eric Anholt Jan. 28, 2021, 9:03 p.m. UTC 
Now that we're not racing with GPU setup, also fix races of timestamps
against other timestamps.  In freedreno CI, we were seeing this path trigger
timeouts on setting the GMU bit, producing:

[drm:_a6xx_gmu_set_oob] *ERROR* Timeout waiting for GMU OOB set GPU_SET: 0x0

and this triggered especially on the first set of tests right after
boot (it's probably easier to lose the race than one might think,
given that we start many tests in parallel, and waiting for NFS to
page in code probably means that lots of tests hit the same point of
screen init at the same time).  As of this patch, the message seems to
have completely gone away.

Signed-off-by: Eric Anholt <eric@anholt.net>
Fixes: 4b565ca5a2cb ("drm/msm: Add A6XX device support")
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 7424a70b9d35..e8f0b5325a7f 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1175,6 +1175,9 @@  static int a6xx_get_timestamp(struct msm_gpu *gpu, uint64_t *value)
 {
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
 	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	static DEFINE_MUTEX(perfcounter_oob);
+
+	mutex_lock(&perfcounter_oob);
 
 	/* Force the GPU power on so we can read this register */
 	a6xx_gmu_set_oob(&a6xx_gpu->gmu, GMU_OOB_PERFCOUNTER_SET);
@@ -1183,6 +1186,7 @@  static int a6xx_get_timestamp(struct msm_gpu *gpu, uint64_t *value)
 		REG_A6XX_RBBM_PERFCTR_CP_0_HI);
 
 	a6xx_gmu_clear_oob(&a6xx_gpu->gmu, GMU_OOB_PERFCOUNTER_SET);
+	mutex_unlock(&perfcounter_oob);
 	return 0;
 }