From: Laurent Pinchart <laurent.pinchart@skynet.be>
To: Mauro Carvalho Chehab <mchehab@infradead.org>
Subject: Re: [PULL] http://www.linuxtv.org/hg/~hverkuil/v4l-dvb-ng
Date: Tue, 2 Dec 2008 17:58:35 +0100
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Cc: Hans Verkuil <hverkuil@xs4all.nl>, video4linux-list@redhat.com,
       "v4l-dvb maintainer list" <v4l-dvb-maintainer@linuxtv.org>,
       "linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
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       davinci-linux-open-source-bounces@linux.davincidsp.com
References: <200812011246.08885.hverkuil@xs4all.nl> <200812011524.43499.laurent.pinchart@skynet.be> <20081201130643.661f5743@pedra.chehab.org>
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Hi Mauro,

On Monday 01 December 2008, Mauro Carvalho Chehab wrote:
> Hi Hans,
>
> On Mon, 1 Dec 2008 15:24:43 +0100
>
> Laurent Pinchart <laurent.pinchart@skynet.be> wrote:
[snip]

> > In a few months time (probably even earlier) the v4l2_device structure
> > will be reworked (and possible renamed).
>
> Hmm... why? it would be better to try to have the KABI changes for it at
> the same kernel release if possible.

Because Hans is working on more changes.

> > I'm fine with it going to linux-next now if
> > we agree on the following.
> >
> > - We should only advocate v4l2_device usage for subdevices-aware video
> > devices. Porting all drivers to v4l2_device is currently pointless and
> > will only make future transitions more difficult.
>
> This makes sense to me.
>
> > - v4l2_device should be marked as experimental. I don't want to hear any
> > API/ABI breakage argument in a few months time when the framework will
> > evolve.
>
> Are you meaning marking this as experimental at Kconfig? This seems too
> complex, since we'll need to test for some var on every driver that were
> converted, providing two KABI options for each converted driver (the legacy
> and the v4l2_device way). This doesn't seem to be a good idea, since will
> add a lot of extra complexity to debug bugs.

Not at the Kconfig level, just in the documentation (and possible headers).

This is a work in progress. Hans wants the changes to go mainline to get 
broader testing, which is a valid reason, but I'd like to make sure people 
understand that more changes are coming.

Best regards,

Laurent Pinchart
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