On 2/14/19 11:07 AM, Michel Dänzer wrote: > 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. Yes, agree. Andrey > > _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
