[Public] Hi Alex/Christian, This patch is to put drm_sched_stop to stop scheduler before amdgpu_fence_wait_empty, otherwise, there is possibly a race problem that drm scheduler will keep submitting commands to hardware in suspend, so amdgpu_fence_wait_empty has no chance to get empty. This is based on the discussion with Andrey before. In Brown's case, without this patch, his test can run well by a 10-hour duration. However, with this patch applied, issue occurs in under an hour. I guess this patch exposes another underlying problem, as if it's totally faulty, the test with the patch applied will break in the first round suspend/resume test instead of failed after several rounds suspend/resume test. https://bugzilla.kernel.org/show_bug.cgi?id=215315 Anyway, we can revert it for now, and I will continue the investigation to the root cause. Regards, Guchun -----Original Message----- From: Deucher, Alexander <Alexander.Deucher@xxxxxxx> Sent: Tuesday, January 11, 2022 12:26 AM To: Koenig, Christian <Christian.Koenig@xxxxxxx>; Len Brown <lenb@xxxxxxxxxx>; torvalds@xxxxxxxxxxxxxxxxxxxx; Chen, Guchun <Guchun.Chen@xxxxxxx>; Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx> Cc: linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Len Brown <len.brown@xxxxxxxxx>; stable@xxxxxxxxxxxxxxx Subject: RE: [PATCH REGRESSION] Revert "drm/amdgpu: stop scheduler when calling hw_fini (v2)" [Public] > -----Original Message----- > From: Koenig, Christian <Christian.Koenig@xxxxxxx> > Sent: Monday, January 10, 2022 11:16 AM > To: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Len Brown > <lenb@xxxxxxxxxx>; torvalds@xxxxxxxxxxxxxxxxxxxx; Chen, Guchun > <Guchun.Chen@xxxxxxx>; Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx> > Cc: linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Len Brown > <len.brown@xxxxxxxxx>; stable@xxxxxxxxxxxxxxx > Subject: Re: [PATCH REGRESSION] Revert "drm/amdgpu: stop scheduler > when calling hw_fini (v2)" > > 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%2Fbug > >> z > illa.kernel.org%2Fshow_bug.cgi%3Fid%3D215315&data=04%7C01%7Cal > >> > exander.deucher%40amd.com%7Ccf790be4827f4df9f2d808d9d39b81af%7C3 > >> > dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637773487569442716%7C > >> > Unknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJB > >> > TiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=AX0TXkyoMhy%2BZqE > >> VgRSWMkKd5nPa4WOv%2B1FZHLSErSw%3D&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. Thanks. I'll wait for feedback from Guchun and Andrey and if they are ok with it, I'll apply the revert. Alex > > 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
