Re: [PATCH 15/24] drm: support more than one write fence in drm_gem_plane_helper_prepare_fb

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Dec 07, 2021 at 01:34:02PM +0100, Christian König wrote:
> Use dma_resv_get_singleton() here to eventually get more than one write
> fence as single fence.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>

Patch title should be drm/atomic-helper: prefix, not just drm:

With that nit:

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/drm_gem_atomic_helper.c | 18 +++++++-----------
>  1 file changed, 7 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c
> index c3189afe10cb..9338ddb7edff 100644
> --- a/drivers/gpu/drm/drm_gem_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
> @@ -143,25 +143,21 @@
>   */
>  int drm_gem_plane_helper_prepare_fb(struct drm_plane *plane, struct drm_plane_state *state)
>  {
> -	struct dma_resv_iter cursor;
>  	struct drm_gem_object *obj;
>  	struct dma_fence *fence;
> +	int ret;
>  
>  	if (!state->fb)
>  		return 0;
>  
>  	obj = drm_gem_fb_get_obj(state->fb, 0);
> -	dma_resv_iter_begin(&cursor, obj->resv, false);
> -	dma_resv_for_each_fence_unlocked(&cursor, fence) {
> -		/* TODO: Currently there should be only one write fence, so this
> -		 * here works fine. But drm_atomic_set_fence_for_plane() should
> -		 * be changed to be able to handle more fences in general for
> -		 * multiple BOs per fb anyway. */
> -		dma_fence_get(fence);
> -		break;
> -	}
> -	dma_resv_iter_end(&cursor);
> +	ret = dma_resv_get_singleton(obj->resv, false, &fence);
> +	if (ret)
> +		return ret;
>  
> +	/* TODO: drm_atomic_set_fence_for_plane() should be changed to be able
> +	 * to handle more fences in general for multiple BOs per fb.
> +	 */
>  	drm_atomic_set_fence_for_plane(state, fence);
>  	return 0;
>  }
> -- 
> 2.25.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch