[PATCH v3 5/5] Patch '5edb0c9b Fix deadlock with display during hanged ring recovery' was accidentaly removed during one of DALs code merges.

[Kazlauskas, Nicholas]

On 4/15/19 3:43 PM, Andrey Grodzovsky wrote:
> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
> Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>

Nitpicks:

Put the current commit message (with the spelling mistake in 
accidentally fixed) in the body of the commit and give the commit title 
something a little more descriptive, eg:

drm/amd/display: Use a reasonable timeout for framebuffer fence waits

The current title's length is a little bit excessive...

Nicholas Kazlauskas

> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 15 +++++++++------
>   1 file changed, 9 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 5aeac2c..2bae2bf 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -5297,11 +5297,16 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
>   
>   		abo = gem_to_amdgpu_bo(fb->obj[0]);
>   
> -		/* Wait for all fences on this FB */
> +		/*
> +		 * Wait for all fences on this FB. Do limited wait to avoid
> +		 * deadlock during GPU reset when this fence will not signal
> +		 * but we hold reservation lock for the BO.
> +		 */
>   		r = reservation_object_wait_timeout_rcu(abo->tbo.resv, true,
>   							false,
> -							MAX_SCHEDULE_TIMEOUT);
> -		WARN_ON(r < 0);
> +							msecs_to_jiffies(5000));
> +		if (unlikely(r <= 0))
> +			DRM_ERROR("Waiting for fences timed out or interrupted!");
>   
>   		/*
>   		 * TODO This might fail and hence better not used, wait
> @@ -5310,10 +5315,8 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
>   		 * blocking commit to as per framework helpers
>   		 */
>   		r = amdgpu_bo_reserve(abo, true);
> -		if (unlikely(r != 0)) {
> +		if (unlikely(r != 0))
>   			DRM_ERROR("failed to reserve buffer before flip\n");
> -			WARN_ON(1);
> -		}
>   
>   		amdgpu_bo_get_tiling_flags(abo, &tiling_flags);
>   
>