[PATCH 3/7] drm/msm: Fix cx collapse issue during recovery

From: Akhil P Oommen
Date: Thu Jul 07 2022 - 12:12:56 EST


There are some hardware logic under CX domain. For a successful
recovery, we should ensure cx headswitch collapses to ensure all the
stale states are cleard out. This is especially true to for a6xx family
where we can GMU co-processor.

Currently, cx doesn't collapse due to a devlink between gpu and its
smmu. So the *struct gpu device* needs to be runtime suspended to ensure
that the iommu driver removes its vote on cx gdsc.

Signed-off-by: Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx>
---

drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 16 ++++++++++++++--
drivers/gpu/drm/msm/msm_gpu.c | 2 --
2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 42ed9a3..57a7ad5 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1210,8 +1210,20 @@ static void a6xx_recover(struct msm_gpu *gpu)
*/
gmu_write(&a6xx_gpu->gmu, REG_A6XX_GMU_GMU_PWR_COL_KEEPALIVE, 0);

- gpu->funcs->pm_suspend(gpu);
- gpu->funcs->pm_resume(gpu);
+ /*
+ * Now drop all the pm_runtime usage count to allow cx gdsc to collapse.
+ * First drop the usage count from all active submits
+ */
+ for (i = gpu->active_submits; i > 0; i--)
+ pm_runtime_put(&gpu->pdev->dev);
+
+ /* And the final one from recover worker */
+ pm_runtime_put_sync(&gpu->pdev->dev);
+
+ for (i = gpu->active_submits; i > 0; i--)
+ pm_runtime_get(&gpu->pdev->dev);
+
+ pm_runtime_get_sync(&gpu->pdev->dev);

msm_gpu_hw_init(gpu);
}
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index f75ff4b..48171b6 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -444,9 +444,7 @@ static void recover_worker(struct kthread_work *work)
/* retire completed submits, plus the one that hung: */
retire_submits(gpu);

- pm_runtime_get_sync(&gpu->pdev->dev);
gpu->funcs->recover(gpu);
- pm_runtime_put_sync(&gpu->pdev->dev);

/*
* Replay all remaining submits starting with highest priority
--
2.7.4