From: Rob Clark robdclark@chromium.org
[ Upstream commit e8b0b994c3a5881f0648d53f90435120089c56ad ]
Clear the shadow rptr on suspend. Otherwise, when we resume, we can have a stale value until CP_WHERE_AM_I executes. If we suspend near the ringbuffer wraparound point, this can lead to a chicken/egg situation where we are waiting for ringbuffer space to write the CP_WHERE_AM_I (or CP_INIT) packet, because we mistakenly believe that the ringbuffer is full (due to stale rptr value in the shadow).
Fixes errors like:
[drm:adreno_wait_ring [msm]] *ERROR* timeout waiting for space in ringbuffer 0
in the resume path.
Fixes: d3a569fccfa0 ("drm/msm: a6xx: Use WHERE_AM_I for eligible targets") Signed-off-by: Rob Clark robdclark@chromium.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c index 948f3656c20ca..420ca4a0eb5f7 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c @@ -1045,12 +1045,21 @@ static int a6xx_pm_suspend(struct msm_gpu *gpu) { struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu); struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu); + int i, ret;
trace_msm_gpu_suspend(0);
devfreq_suspend_device(gpu->devfreq.devfreq);
- return a6xx_gmu_stop(a6xx_gpu); + ret = a6xx_gmu_stop(a6xx_gpu); + if (ret) + return ret; + + if (adreno_gpu->base.hw_apriv || a6xx_gpu->has_whereami) + for (i = 0; i < gpu->nr_rings; i++) + a6xx_gpu->shadow[i] = 0; + + return 0; }
static int a6xx_get_timestamp(struct msm_gpu *gpu, uint64_t *value)