On 6/9/2022 9:24 PM, Rob Clark wrote:

On Thu, Jun 9, 2022 at 7:34 AM Douglas Anderson dianders@chromium.org wrote:

...

From testing on sc7180-trogdor devices, reading the GMU registers needs the GMU clocks to be enabled. Those clocks get turned on in a6xx_gmu_resume(). Confusingly enough, that function is called as a result of the runtime_pm of the GPU "struct device", not the GMU "struct device".

Let's grab a reference to the correct device. Incidentally, this makes us match the a5xx routine more closely.

This is easily shown to fix crashes that happen if we change the GPU's pm_runtime usage to not use autosuspend. It's also believed to fix some long tail GPU crashes even with autosuspend.

NOTE: the crashes I've seen were fixed by _only_ fixing a6xx_gpu_busy(). However, I believe that the same arguments should be made to a6xx_gmu_set_freq() so I've changed that function too.

Fixes: eadf79286a4b ("drm/msm: Check for powered down HW in the devfreq callbacks") Signed-off-by: Douglas Anderson dianders@chromium.org

---

drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 6 +++--- drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c index 9f76f5b15759..b79ad2e0649c 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c @@ -129,13 +129,13 @@ void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp) * This can get called from devfreq while the hardware is idle. Don't * bring up the power if it isn't already active */

•   if (pm_runtime_get_if_in_use(gmu->dev) == 0)
  

•   if (pm_runtime_get_if_in_use(&gpu->pdev->dev) == 0)
  

IMHO, if we do end up using the GPU's runpm instead of the GMU's, we should probably just move this _get_if_in_use() into msm_gpu_devfreq,

+ 1 this.

etc. (And probably also this should be "<= 0".. I have that change locally but haven't sent a patch yet

.. and skip return here when CONFIG_PM is disabled.

-Akhil.

BR, -R

...

             return;

     if (!gmu->legacy) {
             a6xx_hfi_set_freq(gmu, perf_index);
             dev_pm_opp_set_opp(&gpu->pdev->dev, opp);

•           pm_runtime_put(gmu->dev);
  

•           pm_runtime_put(&gpu->pdev->dev);
             return;
     }
  
  

@@ -159,7 +159,7 @@ void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp) dev_err(gmu->dev, "GMU set GPU frequency error: %d\n", ret);

     dev_pm_opp_set_opp(&gpu->pdev->dev, opp);

•   pm_runtime_put(gmu->dev);
  

•   pm_runtime_put(&gpu->pdev->dev);
  

  }

  unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c index 841e47a0b06b..87568d0b6ef8 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c @@ -1659,7 +1659,7 @@ static u64 a6xx_gpu_busy(struct msm_gpu *gpu, unsigned long *out_sample_rate) *out_sample_rate = 19200000;

     /* Only read the gpu busy if the hardware is already active */

•   if (pm_runtime_get_if_in_use(a6xx_gpu->gmu.dev) == 0)
  

•   if (pm_runtime_get_if_in_use(&gpu->pdev->dev) == 0)
             return 0;
  
     busy_cycles = gmu_read64(&a6xx_gpu->gmu,
  

@@ -1667,7 +1667,7 @@ static u64 a6xx_gpu_busy(struct msm_gpu *gpu, unsigned long *out_sample_rate) REG_A6XX_GMU_CX_GMU_POWER_COUNTER_XOCLK_0_H);

•   pm_runtime_put(a6xx_gpu->gmu.dev);
  

•   pm_runtime_put(&gpu->pdev->dev);
  
     return busy_cycles;
  

  }

-- 2.36.1.255.ge46751e96f-goog