lkml.org 
[lkml]   [2022]   [Aug]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH v3 4/8] drm/msm: Fix cx collapse issue during recovery
    From
    On 7/31/2022 9:52 PM, Rob Clark wrote:
    > On Sat, Jul 30, 2022 at 2:41 AM Akhil P Oommen <quic_akhilpo@quicinc.com> wrote:
    >> 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@quicinc.com>
    >> ---
    >>
    >> Changes in v3:
    >> - Simplied the pm refcount drop since we have just a single refcount now
    >> for all active submits
    >>
    >> drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 24 +++++++++++++++++++++---
    >> drivers/gpu/drm/msm/msm_gpu.c | 4 +---
    >> 2 files changed, 22 insertions(+), 6 deletions(-)
    >>
    >> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
    >> index 42ed9a3..1b049c5 100644
    >> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
    >> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
    >> @@ -1193,7 +1193,7 @@ static void a6xx_recover(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;
    >> + int i, active_submits;
    >>
    >> adreno_dump_info(gpu);
    >>
    >> @@ -1210,8 +1210,26 @@ 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);
    >> + pm_runtime_dont_use_autosuspend(&gpu->pdev->dev);
    >> +
    >> + /* active_submit won't change until we make a submission */
    >> + mutex_lock(&gpu->active_lock);
    >> + active_submits = gpu->active_submits;
    >> + mutex_unlock(&gpu->active_lock);
    >> +
    >> + /* Drop the rpm refcount from active submits */
    >> + if (active_submits)
    >> + pm_runtime_put(&gpu->pdev->dev);
    > Couldn't this race with an incoming submit triggering active_submits
    > to transition 0 -> 1? Moving the mutex_unlock() would solve this.
    >
    > Actually, maybe just move the mutex_unlock() to the end of the entire
    > sequence. You could also clear gpu->active_submits and restore it
    > before unlocking, so you can drop the removal of the WARN_ON_ONCE
    > (patch 6/8) which should otherwise be squashed into this patch to keep
    > things bisectable
    Because we are holding gpu->lock, there won't be any new submissions to
    gpu. But I agree with your both suggestions.

    -Akhil.
    >
    >> +
    >> + /* And the final one from recover worker */
    >> + pm_runtime_put_sync(&gpu->pdev->dev);
    >> +
    >> + pm_runtime_use_autosuspend(&gpu->pdev->dev);
    >> +
    >> + if (active_submits)
    >> + 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 1945efb..07e55a6 100644
    >> --- a/drivers/gpu/drm/msm/msm_gpu.c
    >> +++ b/drivers/gpu/drm/msm/msm_gpu.c
    >> @@ -426,9 +426,7 @@ 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);
    > Hmm, could this have some fallout on earlier gens?
    >
    > I guess I should extend the igt msm_recovery test to run on things
    > prior to a6xx..
    >
    > BR,
    > -R
    No, because of patch 3/8 in this series.

    -Akhil.
    >
    >> /*
    >> * Replay all remaining submits starting with highest priority
    >> @@ -445,7 +443,7 @@ static void recover_worker(struct kthread_work *work)
    >> }
    >> }
    >>
    >> - pm_runtime_put_sync(&gpu->pdev->dev);
    >> + pm_runtime_put(&gpu->pdev->dev);
    >>
    >> mutex_unlock(&gpu->lock);
    >>
    >> --
    >> 2.7.4
    >>

    \
     
     \ /
      Last update: 2022-08-01 17:11    [W:2.374 / U:0.592 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site