linux-kernel - Re: [PATCH] drm/i2c: tda998x: don't register the connector

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Message-ID: <20160809060724.GD6232@phenom.ffwll.local>
Date:	Tue, 9 Aug 2016 08:07:24 +0200
From:	Daniel Vetter <daniel@...ll.ch>
To:	Brian Starkey <brian.starkey@....com>
Cc:	daniel@...ll.ch, Russell King - ARM Linux <linux@...linux.org.uk>,
	Liviu.Dudau@....com, linux-kernel@...r.kernel.org,
	dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] drm/i2c: tda998x: don't register the connector

On Mon, Aug 08, 2016 at 05:04:03PM +0100, Brian Starkey wrote:
> Hi,
> 
> On Mon, Jul 25, 2016 at 05:08:21PM +0200, Daniel Vetter wrote:
> > On Mon, Jul 25, 2016 at 01:54:06PM +0100, Brian Starkey wrote:
> > > Hi Russell,
> > > 
> > > On Mon, Jul 25, 2016 at 01:25:04PM +0100, Russell King - ARM Linux wrote:
> > > > On Mon, Jul 25, 2016 at 11:55:48AM +0100, Brian Starkey wrote:
> > > > > The connector shouldn't be registered until the rest of the whole device
> > > > > is set up, so that consistent state is presented to userspace.
> > > > >
> > > > > As drm_dev_register() now registers all of the connectors anyway,
> > > > > there's no need to explicitly do it in individual drivers so remove
> > > > > the calls to drm_connector_register()/drm_connector_unregister().
> > > > >
> > > > > This allows componentised drivers to use tda998x without having racy
> > > > > initialisation.
> > > >
> > > > Is there a corresponding patch for armada-drm so that the cubox doesn't
> > > > regress?  Has it already been merged?
> > > >
> > > 
> > > A patch for armada-drm to do what?
> > > 
> > > I should perhaps have explicitly mentioned that this change depends
> > > on e28cd4d0a223: "drm: Automatically register/unregister all
> > > connectors", which is in drm-next.
> > > 
> > > Like my commit message says - after the above commit, all connectors
> > > are automatically registered in drm_dev_register() - so I don't
> > > anticipate any regression, but I don't have a cubox to test.
> > > 
> > > armada-drm seems to be doing effectively the same thing as arm/hdlcd,
> > > which works fine after this patch with no other changes.
> > > 
> > > Let me know if I've missed something; or if you are able to test on
> > > cubox that would be great.
> > 
> > Ack from my side on generally nuking drm_connector_register() from
> > everywhere except truely hotplugged connectors like dp mst. It should keep
> > working for everyone. Only exception is if there's a driver which calls
> > drm_dev_register too early (before all connectors are probed), which would
> > be a bug anyway.
> 
> Right; the motivation for this change is to fix the init order in
> HDLCD and Mali-DP (move drm_dev_register to the end), which we can't
> do right now because tda998x expects the DRM device sysfs to be set
> up in bind.
> 
> @Daniel: Can I take this as your Acked-by?

Sure.

> Should this go in via Russell's tree?

I can also throw it into drm-misc, if Russell (or someone else) can
provide a tested-by for armada. Better safe than sorry ;-)
-Daniel

> 
> @Russell, are you happy with this change?
> 
> Thanks,
> Brian
> 
> > -Daniel
> > -- 
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
> > 

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