On Mon, Dec 18, 2023 at 07:59:24AM -0800, Rob Clark wrote: > > From: Rob Clark <robdcl...@chromium.org> > > a6xx_recover() is relying on the gpu lock to serialize against incoming > submits doing a runpm get, as it tries to temporarily balance out the > runpm gets with puts in order to power off the GPU. Unfortunately this > gets worse when we (in a later patch) will move the runpm get out of the > scheduler thread/work to move it out of the fence signaling path. > > Instead we can just simplify the whole thing by using force_suspend() / > force_resume() instead of trying to be clever.
At some places, we take a pm_runtime vote and access the gpu registers assuming it will be powered until we drop the vote. a6xx_get_timestamp() is an example. If we do a force suspend, it may cause bus errors from those threads. Now you have to serialize every place we do runtime_get/put with a mutex. Or is there a better way to handle the 'later patch' you mentioned? -Akhil. > > Reported-by: David Heidelberg <david.heidelb...@collabora.com> > Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/10272 > Fixes: abe2023b4cea ("drm/msm/gpu: Push gpu lock down past runpm") > Signed-off-by: Rob Clark <robdcl...@chromium.org> > --- > drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 12 ++---------- > 1 file changed, 2 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > index 268737e59131..a5660d63535b 100644 > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > @@ -1244,12 +1244,7 @@ static void a6xx_recover(struct msm_gpu *gpu) > dev_pm_genpd_add_notifier(gmu->cxpd, &gmu->pd_nb); > dev_pm_genpd_synced_poweroff(gmu->cxpd); > > - /* Drop the rpm refcount from active submits */ > - if (active_submits) > - pm_runtime_put(&gpu->pdev->dev); > - > - /* And the final one from recover worker */ > - pm_runtime_put_sync(&gpu->pdev->dev); > + pm_runtime_force_suspend(&gpu->pdev->dev); > > if (!wait_for_completion_timeout(&gmu->pd_gate, msecs_to_jiffies(1000))) > DRM_DEV_ERROR(&gpu->pdev->dev, "cx gdsc didn't collapse\n"); > @@ -1258,10 +1253,7 @@ static void a6xx_recover(struct msm_gpu *gpu) > > pm_runtime_use_autosuspend(&gpu->pdev->dev); > > - if (active_submits) > - pm_runtime_get(&gpu->pdev->dev); > - > - pm_runtime_get_sync(&gpu->pdev->dev); > + pm_runtime_force_resume(&gpu->pdev->dev); > > gpu->active_submits = active_submits; > mutex_unlock(&gpu->active_lock); > -- > 2.43.0 >
