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

[Daniel Vetter]

On Fri, Oct 28, 2016 at 09:30:26AM +0200, Daniel Vetter wrote:
> 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() */

Ok, small bikeshed maybe: When you feel the need to add more comments
in-line in a struct, then please switch to the in-line kernel-doc member
documentation style, and merge the existing kerneldoc together with these
additional comments. Would be great to do that with all the others here
too. Follow-up patch to address this would be great.
-Daniel

> >  
> >  	/* 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

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