[PATCH v5 1/6] drm/amd/display: wait for fence without holding reservation lock

[Dieter Nützel]

Hello Andrey,

this series can't apply (brake on #3) on top of amd-staging-drm-next.
v2 works (Thu, 11 Apr 2019).

Dieter

Am 18.04.2019 17:00, schrieb Andrey Grodzovsky:
> From: Christian König <ckoenig.leichtzumerken at gmail.com>
> 
> Don't block others while waiting for the fences to finish, concurrent
> submission is perfectly valid in this case and holding the lock can
> prevent killed applications from terminating.
> 
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
> ---
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 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 380a7f9..ad4f0e5 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -4814,23 +4814,26 @@ static void amdgpu_dm_commit_planes(struct
> drm_atomic_state *state,
>  			continue;
>  		}
> 
> +		abo = gem_to_amdgpu_bo(fb->obj[0]);
> +
> +		/* Wait for all fences on this FB */
> +		r = reservation_object_wait_timeout_rcu(abo->tbo.resv, true,
> +							false,
> +							MAX_SCHEDULE_TIMEOUT);
> +		WARN_ON(r < 0);
> +
>  		/*
>  		 * TODO This might fail and hence better not used, wait
>  		 * explicitly on fences instead
>  		 * and in general should be called for
>  		 * blocking commit to as per framework helpers
>  		 */
> -		abo = gem_to_amdgpu_bo(fb->obj[0]);
>  		r = amdgpu_bo_reserve(abo, true);
>  		if (unlikely(r != 0)) {
>  			DRM_ERROR("failed to reserve buffer before flip\n");
>  			WARN_ON(1);
>  		}
> 
> -		/* Wait for all fences on this FB */
> -		WARN_ON(reservation_object_wait_timeout_rcu(abo->tbo.resv, true, 
> false,
> -									    MAX_SCHEDULE_TIMEOUT) < 0);
> -
>  		amdgpu_bo_get_tiling_flags(abo, &tiling_flags);
> 
>  		amdgpu_bo_unreserve(abo);