Re: [PATCH] drm/doc: Improve docs for conn_state->best_encoder

From: Daniel Vetter <daniel@ffwll.ch>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
	Sean Paul <sean@poorly.run>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH] drm/doc: Improve docs for conn_state->best_encoder
Date: Tue, 7 May 2019 12:02:39 +0200	[thread overview]
Message-ID: <20190507100238.GO17751@phenom.ffwll.local> (raw)
In-Reply-To: <20190506152724.GK17751@phenom.ffwll.local>

On Mon, May 06, 2019 at 05:27:24PM +0200, Daniel Vetter wrote:
> On Mon, May 06, 2019 at 05:57:53PM +0300, Laurent Pinchart wrote:
> > Hi Daniel,
> > 
> > Thank you for the patch.
> > 
> > On Mon, May 06, 2019 at 04:46:29PM +0200, Daniel Vetter wrote:
> > > It's mandatory and considered core state since ioctls rely on this
> > > working.
> > > 
> > > Thanks to Laurent for pointing out this gap.
> > > 
> > > v2: Clarify to "atomic drivers" only.
> > > 
> > > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > Cc: Sean Paul <sean@poorly.run>
> > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > > ---
> > >  include/drm/drm_connector.h | 4 ++++
> > >  1 file changed, 4 insertions(+)
> > > 
> > > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> > > index 02a131202add..f43f40d5888a 100644
> > > --- a/include/drm/drm_connector.h
> > > +++ b/include/drm/drm_connector.h
> > > @@ -517,6 +517,10 @@ struct drm_connector_state {
> > >  	 * Used by the atomic helpers to select the encoder, through the
> > >  	 * &drm_connector_helper_funcs.atomic_best_encoder or
> > >  	 * &drm_connector_helper_funcs.best_encoder callbacks.
> > 
> > How about updating this part as well ?
> > 
> > "Used by both the DRM core and the atomic helpers to select the encoder
> > (through the &drm_connector_helper_funcs.atomic_best_encoder), access it
> > and report it to userspace (through the GETCONNECTOR and GETENCODER
> > ioctls). This field shall be set by all atomic drivers, either directly
> > or through atomic helpers."
> 
> It's kinda two things, I think best to describe in two paragraphs. But I
> can move the core usage up, since arguable more important. Otoh most
> drivers won't care since helpers handle this, and they care more about how
> @best_encoder is used.
> 
> E.g. core never calls the helper callbacks
> @atomic_best_endoer/best_encoder, which isn't clear anymore with your
> wording. And I have a sticker for core/helper splits :-)

Went ahead with Sean's irc ack and merged this. We can bikeshed more later
on I guess with more patches. I think sprinkling a pile of cross
references once Sean's and yours patches all land would be good.
-Daniel

> -Daniel
> > 
> > > +	 *
> > > +	 * NOTE: Atomic drivers must fill this out (either themselves or through
> > > +	 * helpers), for otherwise the GETCONNECTOR and GETENCODER IOCTLs will
> > > +	 * not return correct data to userspace.
> > >  	 */
> > >  	struct drm_encoder *best_encoder;
> > >  
> > 
> > -- 
> > Regards,
> > 
> > Laurent Pinchart
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

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