On Wed, 23 Feb 2022 at 18:46, Rob Clark robdclark@gmail.com wrote:

On Tue, Feb 22, 2022 at 7:11 PM Dmitry Baryshkov dmitry.baryshkov@linaro.org wrote:

...

On 19/02/2022 21:33, Rob Clark wrote:

...

From: Rob Clark robdclark@chromium.org

Avoid going down devfreq paths on devices where devfreq is not initialized.

Reported-by: Linux Kernel Functional Testing lkft@linaro.org Reported-by: Anders Roxell anders.roxell@linaro.org Signed-off-by: Rob Clark robdclark@chromium.org

---

drivers/gpu/drm/msm/msm_gpu_devfreq.c | 31 +++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c b/drivers/gpu/drm/msm/msm_gpu_devfreq.c index 9bf319be11f6..26a3669a97b3 100644 --- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c +++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c @@ -83,12 +83,17 @@ static struct devfreq_dev_profile msm_devfreq_profile = { static void msm_devfreq_boost_work(struct kthread_work *work); static void msm_devfreq_idle_work(struct kthread_work *work);

+static bool has_devfreq(struct msm_gpu *gpu) +{

• return !!gpu->funcs->gpu_busy;
  

I see that devfreq init will be skipped if gpu_busy is NULL. Can we use gpu->devfreq instead of this condition?

We could, but then we couldn't also use the same has_devfreq() helper in msm_devfreq_init(). I thought it was clearer to use the same helper everywhere.

Well... It is not clear at first glance how gpu_busy is related to devfreq. On the other hand, if gpu->devfreq is NULL, it's obvious that devfreq is not initialized.

I'd propose to use if (gpu->funcs->gpu_busy) to check if we can init devfreq and after that to check (gpu->devfreq) as a way to know whether the devfreq is available.

...

I noticed that you have replaced some of gpu->devfreq checks with has_devreq() calls. Is there any difference?

It amounts to the same thing because if you don't have gpu_busy, then devfreq is never initialized. I just thought it clearer to use the same check in all places.

See my comment above.

BR, -R

...

...

+}

• void msm_devfreq_init(struct msm_gpu *gpu) { struct msm_gpu_devfreq *df = &gpu->devfreq;

  /* We need target support to do devfreq */
  

• if (!gpu->funcs->gpu_busy)
  

• if (!has_devfreq(gpu))
          return;
  
  dev_pm_qos_add_request(&gpu->pdev->dev, &df->idle_freq,
  

@@ -149,6 +154,9 @@ void msm_devfreq_cleanup(struct msm_gpu *gpu) { struct msm_gpu_devfreq *df = &gpu->devfreq;

• if (!has_devfreq(gpu))
  

•         return;
  

• devfreq_cooling_unregister(gpu->cooling);
  dev_pm_qos_remove_request(&df->boost_freq);
  dev_pm_qos_remove_request(&df->idle_freq);
  

@@ -156,16 +164,24 @@ void msm_devfreq_cleanup(struct msm_gpu *gpu)

void msm_devfreq_resume(struct msm_gpu *gpu) {

• gpu->devfreq.busy_cycles = 0;
  

• gpu->devfreq.time = ktime_get();
  

• struct msm_gpu_devfreq *df = &gpu->devfreq;
  
  

• devfreq_resume_device(gpu->devfreq.devfreq);
  

• if (!has_devfreq(gpu))
  

•         return;
  

• df->busy_cycles = 0;
  

• df->time = ktime_get();
  

• devfreq_resume_device(df->devfreq);
  

  }

  void msm_devfreq_suspend(struct msm_gpu *gpu) { struct msm_gpu_devfreq *df = &gpu->devfreq;

• if (!has_devfreq(gpu))
  

•         return;
  

• devfreq_suspend_device(df->devfreq);
  
  cancel_idle_work(df);
  

@@ -185,6 +201,9 @@ void msm_devfreq_boost(struct msm_gpu *gpu, unsigned factor) struct msm_gpu_devfreq *df = &gpu->devfreq; uint64_t freq;

• if (!has_devfreq(gpu))
  

•         return;
  

• freq = get_freq(gpu);
  freq *= factor;
  
  

@@ -207,7 +226,7 @@ void msm_devfreq_active(struct msm_gpu *gpu) struct devfreq_dev_status status; unsigned int idle_time;

• if (!df->devfreq)
  

• if (!has_devfreq(gpu))
          return;
  
  /*
  

@@ -253,7 +272,7 @@ void msm_devfreq_idle(struct msm_gpu *gpu) { struct msm_gpu_devfreq *df = &gpu->devfreq;

• if (!df->devfreq)
  

• if (!has_devfreq(gpu))
          return;
  
  msm_hrtimer_queue_work(&df->idle_work, ms_to_ktime(1),
  

-- With best wishes Dmitry

Hi Rob and Linus,

On Mon, 7 Mar 2022 at 14:07, Naresh Kamboju naresh.kamboju@linaro.org wrote:

Hi Rob,

On Sun, 20 Feb 2022 at 00:02, Rob Clark robdclark@gmail.com wrote:

...

From: Rob Clark robdclark@chromium.org

Avoid going down devfreq paths on devices where devfreq is not initialized.

Reported-by: Linux Kernel Functional Testing lkft@linaro.org Reported-by: Anders Roxell anders.roxell@linaro.org Signed-off-by: Rob Clark robdclark@chromium.org

I have tested this patch and the reported kernel crash is fixed [1].

Tested-by: Linux Kernel Functional Testing lkft@linaro.org

...

---

drivers/gpu/drm/msm/msm_gpu_devfreq.c | 31 +++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c b/drivers/gpu/drm/msm/msm_gpu_devfreq.c index 9bf319be11f6..26a3669a97b3 100644 --- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c +++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c @@ -83,12 +83,17 @@ static struct devfreq_dev_profile msm_devfreq_profile = { static void msm_devfreq_boost_work(struct kthread_work *work); static void msm_devfreq_idle_work(struct kthread_work *work);

+static bool has_devfreq(struct msm_gpu *gpu) +{

•   return !!gpu->funcs->gpu_busy;
  

+}

void msm_devfreq_init(struct msm_gpu *gpu) { struct msm_gpu_devfreq *df = &gpu->devfreq;

    /* We need target support to do devfreq */

•   if (!gpu->funcs->gpu_busy)
  

•   if (!has_devfreq(gpu))
            return;
  
    dev_pm_qos_add_request(&gpu->pdev->dev, &df->idle_freq,
  

@@ -149,6 +154,9 @@ void msm_devfreq_cleanup(struct msm_gpu *gpu) { struct msm_gpu_devfreq *df = &gpu->devfreq;

•   if (!has_devfreq(gpu))
  

•           return;
  

•   devfreq_cooling_unregister(gpu->cooling);
    dev_pm_qos_remove_request(&df->boost_freq);
    dev_pm_qos_remove_request(&df->idle_freq);
  

@@ -156,16 +164,24 @@ void msm_devfreq_cleanup(struct msm_gpu *gpu)

void msm_devfreq_resume(struct msm_gpu *gpu) {

•   gpu->devfreq.busy_cycles = 0;
  

•   gpu->devfreq.time = ktime_get();
  

•   struct msm_gpu_devfreq *df = &gpu->devfreq;
  
  

•   devfreq_resume_device(gpu->devfreq.devfreq);
  

•   if (!has_devfreq(gpu))
  

•           return;
  

•   df->busy_cycles = 0;
  

•   df->time = ktime_get();
  

•   devfreq_resume_device(df->devfreq);
  

}

void msm_devfreq_suspend(struct msm_gpu *gpu) { struct msm_gpu_devfreq *df = &gpu->devfreq;

•   if (!has_devfreq(gpu))
  

•           return;
  

•   devfreq_suspend_device(df->devfreq);
  
    cancel_idle_work(df);
  

@@ -185,6 +201,9 @@ void msm_devfreq_boost(struct msm_gpu *gpu, unsigned factor) struct msm_gpu_devfreq *df = &gpu->devfreq; uint64_t freq;

•   if (!has_devfreq(gpu))
  

•           return;
  

•   freq = get_freq(gpu);
    freq *= factor;
  
  

@@ -207,7 +226,7 @@ void msm_devfreq_active(struct msm_gpu *gpu) struct devfreq_dev_status status; unsigned int idle_time;

•   if (!df->devfreq)
  

•   if (!has_devfreq(gpu))
            return;
  
    /*
  

@@ -253,7 +272,7 @@ void msm_devfreq_idle(struct msm_gpu *gpu) { struct msm_gpu_devfreq *df = &gpu->devfreq;

•   if (!df->devfreq)
  

•   if (!has_devfreq(gpu))
            return;
  
    msm_hrtimer_queue_work(&df->idle_work, ms_to_ktime(1),
  

FYI, This patch is missing on Linux 5.17-rc8 [1]. kernel crash log on arm64 db410c device [2] and details [3].

metadata: git_describe: v5.17-rc8 git_ref: master git_repo: https://gitlab.com/Linaro/lkft/mirrors/torvalds/linux-mainline git_sha: 09688c0166e76ce2fb85e86b9d99be8b0084cdf9 kernel-config: https://builds.tuxbuild.com/26LbbVLHqxjh5w5ZtjBMjGmh92P/config build: https://builds.tuxbuild.com/26LbbVLHqxjh5w5ZtjBMjGmh92P

- Naresh [1] https://lore.kernel.org/dri-devel/20220219183310.557435-1-robdclark@gmail.co... [2] https://lkft.validation.linaro.org/scheduler/job/4714905#L2795 [3] https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v5.17-rc8/tes...

-- Linaro LKFT https://lkft.linaro.org

[1] https://lkft.validation.linaro.org/scheduler/job/4664600#L1894