Re: [PATCH v6 1/6] drm/atomic: add drm_atomic_set_fence_for_plane()

[Daniel Vetter]

On Thu, Oct 27, 2016 at 05:37:06PM -0200, Gustavo Padovan wrote:
> From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
> 
> This new function should be used by drivers when setting a implicit
> fence for the plane. It abstracts the fact that the user might have
> chosen explicit fencing instead.
> 
> Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>

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

> ---
>  drivers/gpu/drm/drm_atomic.c | 30 ++++++++++++++++++++++++++++++
>  include/drm/drm_atomic.h     |  2 ++
>  include/drm/drm_plane.h      |  2 +-
>  3 files changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index c32fb3c..5e73954 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -1147,6 +1147,36 @@ drm_atomic_set_fb_for_plane(struct drm_plane_state *plane_state,
>  EXPORT_SYMBOL(drm_atomic_set_fb_for_plane);
>  
>  /**
> + * drm_atomic_set_fence_for_plane - set fence for plane
> + * @plane_state: atomic state object for the plane
> + * @fence: dma_fence to use for the plane
> + *
> + * Helper to setup the plane_state fence in case it is not set yet.
> + * By using this drivers doesn't need to worry if the user choose
> + * implicit or explicit fencing.
> + *
> + * This function will not set the fence to the state if it was set
> + * via explicit fencing interfaces on the atomic ioctl. It will
> + * all drope the reference to the fence as we not storing it
> + * anywhere.
> + *
> + * Otherwise, if plane_state->fence is not set this function we
> + * just set it with the received implict fence.
> + */
> +void
> +drm_atomic_set_fence_for_plane(struct drm_plane_state *plane_state,
> +			       struct dma_fence *fence)
> +{
> +	if (plane_state->fence) {
> +		dma_fence_put(fence);
> +		return;
> +	}
> +
> +	plane_state->fence = fence;
> +}
> +EXPORT_SYMBOL(drm_atomic_set_fence_for_plane);
> +
> +/**
>   * drm_atomic_set_crtc_for_connector - set crtc for connector
>   * @conn_state: atomic state object for the connector
>   * @crtc: crtc to use for the connector
> diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> index fc8af53..2d1e9c9 100644
> --- a/include/drm/drm_atomic.h
> +++ b/include/drm/drm_atomic.h
> @@ -345,6 +345,8 @@ drm_atomic_set_crtc_for_plane(struct drm_plane_state *plane_state,
>  			      struct drm_crtc *crtc);
>  void drm_atomic_set_fb_for_plane(struct drm_plane_state *plane_state,
>  				 struct drm_framebuffer *fb);
> +void drm_atomic_set_fence_for_plane(struct drm_plane_state *plane_state,
> +				    struct dma_fence *fence);
>  int __must_check
>  drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
>  				  struct drm_crtc *crtc);
> diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
> index c5e8a0d..68f6d22 100644
> --- a/include/drm/drm_plane.h
> +++ b/include/drm/drm_plane.h
> @@ -59,7 +59,7 @@ struct drm_plane_state {
>  
>  	struct drm_crtc *crtc;   /* do not write directly, use drm_atomic_set_crtc_for_plane() */
>  	struct drm_framebuffer *fb;  /* do not write directly, use drm_atomic_set_fb_for_plane() */
> -	struct dma_fence *fence;
> +	struct dma_fence *fence; /* do not write directly, use drm_atomic_set_fence_for_plane() */
>  
>  	/* Signed dest location allows it to be partially off screen */
>  	int32_t crtc_x, crtc_y;
> -- 
> 2.5.5
> 

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