On 2019-02-14 4:54 p.m., Kazlauskas, Nicholas wrote: > On 2/14/19 10:42 AM, Grodzovsky, Andrey wrote: >> On 2/14/19 4:05 AM, Christian König wrote: >>> Am 13.02.19 um 19:58 schrieb Andrey Grodzovsky: >>>> When ring hang happens amdgpu_dm_commit_planes during flip is holding >>>> the BO reserved and then stack waiting for fences to signal in >>>> reservation_object_wait_timeout_rcu (which won't signal because there >>>> was a hnag). Then when we try to shutdown display block during reset >>>> recovery from drm_atomic_helper_suspend we also try to reserve the BO >>>> from dm_plane_helper_cleanup_fb ending in deadlock. >>>> Also remove useless WARN_ON >>> >>> Well it is good that you pointed this out, but there are more problems >>> than just waiting wile the BO is reserved here. >>> >>>> >>>> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx> >>>> --- >>>> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 19 >>>> +++++++++++++------ >>>> 1 file changed, 13 insertions(+), 6 deletions(-) >>>> >>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >>>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >>>> index acc4ff8..f8dec36 100644 >>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >>>> @@ -4802,14 +4802,21 @@ static void amdgpu_dm_commit_planes(struct >>>> drm_atomic_state *state, >>>> */ >>>> abo = gem_to_amdgpu_bo(fb->obj[0]); >>>> r = amdgpu_bo_reserve(abo, true); >>> >>> Well why do we reserve the BO in the first place? As the name >>> indicates reservation_object_wait_timeout_rcu() just uses rcu to wait >>> for the BO to be idle, no need to actually reserve it at all. >> >> That a good point, I honestly can't remember any more why it's here... >> It does look unnecessary given that we are not validating the BO here. > > I think we reserve it to grab the tiling flags to update the plane > address (and some other bits of the plane state with a patch I'm > currently working on). I'm guessing that we still need the reservation > so nothing else tries to grab it after it becomes idle, but I'm not > overly familiar with that bit. The BO is already pinned at this point, isn't it? That's enough to prevent it from moving, no reservation needed. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
