Re: [PATCH 05/36] drm/atomic: Add drm_atomic_plane_get_crtc_state()

[Thierry Reding]

On Tue, Jan 20, 2015 at 12:10:11PM +0100, Daniel Vetter wrote:
> On Tue, Jan 20, 2015 at 11:48:24AM +0100, Thierry Reding wrote:
> > From: Thierry Reding <treding@xxxxxxxxxx>
> > 
> > This function is useful to obtain the state of the CRTC that a plane is
> > being attached to.
> > 
> > Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> > ---
> >  include/drm/drm_atomic.h | 21 +++++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> > 
> > diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> > index 51168a8b723a..ddca107e5cce 100644
> > --- a/include/drm/drm_atomic.h
> > +++ b/include/drm/drm_atomic.h
> > @@ -75,4 +75,25 @@ int __must_check drm_atomic_check_only(struct drm_atomic_state *state);
> >  int __must_check drm_atomic_commit(struct drm_atomic_state *state);
> >  int __must_check drm_atomic_async_commit(struct drm_atomic_state *state);
> >  
> > +/**
> > + * drm_atomic_plane_get_crtc_state - obtain atomic state of the CRTC that a
> > + *     plane is being attached to
> > + * @state: atomic state of plane
> > + *
> > + * Getting the atomic state of the CRTC that a given plane being attached to
> > + * is non-trivial. We need to look at the global atomic state that the plane
> > + * state is part of and extract the CRTC state using the CRTC's index. Using
> > + * the drm_atomic_get_crtc_state() helper we make sure to acquire the proper
> > + * locks, too.
> > + *
> > + * RETURNS:
> > + * The atomic state of the CRTC that the plane is being attached to, or an
> > + * ERR_PTR()-encoded negative error code on failure.
> > + */
> > +static inline struct drm_crtc_state *
> > +drm_atomic_plane_get_crtc_state(struct drm_plane_state *state)
> > +{
> > +	return drm_atomic_get_crtc_state(state->state, state->crtc);
> 
> Hm, imo open-coding this is totally ok. Actually better since state->crtc
> might be NULL, and hiding that isn't a good idea.
> 
> If you have a atomic_plane_disable hook then ->crtc is guaranteed to be
> non-NULL in atomic_plane_update, but being explicit here is imo a feature.
> So nacked from my side.

I've dropped this patch and open-coded this call in patch 34/36.

Thierry

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