Splitting stk1160-ac97 as a module (Re: linux-next: Tree for May 1 (media/usb/stk1160))

From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
To: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: "Randy Dunlap" <rdunlap@infradead.org>,
	"Yann E. MORIN" <yann.morin.1998@free.fr>,
	"Ezequiel García" <elezegarcia@gmail.com>,
	"Stephen Rothwell" <sfr@canb.auug.org.au>,
	linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-media <linux-media@vger.kernel.org>,
	linux-kbuild@vger.kernel.org
Subject: Splitting stk1160-ac97 as a module (Re: linux-next: Tree for May 1 (media/usb/stk1160))
Date: Sat, 4 May 2013 14:21:44 -0300	[thread overview]
Message-ID: <20130504172142.GA21656@localhost> (raw)
In-Reply-To: <51827DB1.7000304@redhat.com>

Hi Mauro,

On Thu, May 02, 2013 at 11:52:33AM -0300, Mauro Carvalho Chehab wrote:
> >
> > is unreliable (doesn't do what some people expect) when SND=m and SND_AC97_CODEC=m,
> > since VIDEO_STK1160_AC97 is a bool.
> 
> Using select is always tricky.
> 
> I can see a few possible fixes for it:
> 
> 1) split the alsa part into a separate module. IMHO, this is cleaner,
> but requires a little more work.
> 

I'm trying to split the ac97 support into a separate module.
So far I've managed to do this with two different approaches,
but both of them are broken in some way :-(

Couple questions:

1. Is it possible to force two symbols to be both built-in (=y) or both
modules (=m)? This would make one of my solutions work.

2. Do you think it's possible to split this as a module *without*
requesting the driver dynamically? I've tried the same extensions approach
as in em28xx and others, but found some problems with the way
snd-usb-audio driver registers.

Thanks,
-- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com