Re: [PATCH REGRESSION] Revert "drm/amdgpu: stop scheduler when calling hw_fini (v2)"

[Christian König]

Am 10.01.22 um 17:08 schrieb Deucher, Alexander:
> [Public]
>
> > -----Original Message-----
> > From: Len Brown <lenb417@xxxxxxxxx> On Behalf Of Len Brown
> > Sent: Sunday, January 9, 2022 1:12 PM
> > To: torvalds@xxxxxxxxxxxxxxxxxxxx
> > Cc: linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Len Brown
> > <len.brown@xxxxxxxxx>; Chen, Guchun <Guchun.Chen@xxxxxxx>;
> > Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx>; Koenig, Christian
> > <Christian.Koenig@xxxxxxx>; Deucher, Alexander
> > <Alexander.Deucher@xxxxxxx>; stable@xxxxxxxxxxxxxxx
> > Subject: [PATCH REGRESSION] Revert "drm/amdgpu: stop scheduler when
> > calling hw_fini (v2)"
> >
> > From: Len Brown <len.brown@xxxxxxxxx>
> >
> > This reverts commit f7d6779df642720e22bffd449e683bb8690bd3bf.
> >
> > This bisected regression has impacted suspend-resume stability since 5.15-
> > rc1. It regressed -stable via 5.14.10.
> >
> > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugz
> > illa.kernel.org%2Fshow_bug.cgi%3Fid%3D215315&amp;data=04%7C01%7Cal
> > exander.deucher%40amd.com%7Ccf790be4827f4df9f2d808d9d39b81af%7C3
> > dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637773487569442716%7C
> > Unknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJB
> > TiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=AX0TXkyoMhy%2BZqE
> > VgRSWMkKd5nPa4WOv%2B1FZHLSErSw%3D&amp;reserved=0
> >
> > Fixes: f7d6779df64 ("drm/amdgpu: stop scheduler when calling hw_fini (v2)")
> > Cc: Guchun Chen <guchun.chen@xxxxxxx>
> > Cc: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>
> > Cc: Christian Koenig <christian.koenig@xxxxxxx>
> > Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx> # 5.14+
> > Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
> @Chen, Guchun, @Grodzovsky, Andrey, @Koenig, Christian
>
> Any ideas?  What's the consequence of reverting this patch?  Didn't this patch fix another suspend/resume issue?

I think Guchun was just trying to adapt that we removed the scheduler 
stop from the fence driver hw fini path.

Not sure if that actually fixed something or was just a precaution.

Regards,
Christian.

> Alex
>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 8 --------
> >   1 file changed, 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > index 9afd11ca2709..45977a72b5dd 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > @@ -547,9 +547,6 @@ void amdgpu_fence_driver_hw_fini(struct
> > amdgpu_device *adev)
> >   		if (!ring || !ring->fence_drv.initialized)
> >   			continue;
> >
> > -		if (!ring->no_scheduler)
> > -			drm_sched_stop(&ring->sched, NULL);
> > -
> >   		/* You can't wait for HW to signal if it's gone */
> >   		if (!drm_dev_is_unplugged(adev_to_drm(adev)))
> >   			r = amdgpu_fence_wait_empty(ring);
> > @@ -609,11 +606,6 @@ void amdgpu_fence_driver_hw_init(struct
> > amdgpu_device *adev)
> >   		if (!ring || !ring->fence_drv.initialized)
> >   			continue;
> >
> > -		if (!ring->no_scheduler) {
> > -			drm_sched_resubmit_jobs(&ring->sched);
> > -			drm_sched_start(&ring->sched, true);
> > -		}
> > -
> >   		/* enable the interrupt */
> >   		if (ring->fence_drv.irq_src)
> >   			amdgpu_irq_get(adev, ring->fence_drv.irq_src,
> > --
> > 2.25.1