Re: [PATCH] AC97 bus interface for ad-hoc drivers

[Liam Girdwood <liam.girdwood@wolfsonmicro.com>]

On Wed, 2005-07-27 at 15:18 +0200, Takashi Iwai wrote:
> At Wed, 27 Jul 2005 09:05:33 -0400 (EDT),
> Nicolas Pitre wrote:
> > 
> > On Wed, 27 Jul 2005, Takashi Iwai wrote:
> > 
> > > At Tue, 19 Jul 2005 13:20:24 +0100,
> > > Liam Girdwood wrote:
> > > > 
> > > > This patch adds support for ad-hoc AC97 device drivers (e.g WM97xx and
> > > > UCB touchscreen drivers) and was originally posted to the list by
> > > > Nicolas Pitre as an RFC. 
> > > > 
> > > > Changes from RFC version :-
> > > > 
> > > >   o Now matches codec name within codec group.
> > > >   o Added ac97_dev_release() to stop kernel complaining about no release
> > > > method for device.
> > > 
> > > Thanks for the patch.  The idea is fine, and the code looks almost
> > > OK except for the below.
> > > 
> > > Could you describe the full changelog (or paste Nicolas' RFC) ?
> > > 
> > > 
> > > > diff --git a/sound/pci/ac97/Makefile b/sound/pci/ac97/Makefile
> > > > --- a/sound/pci/ac97/Makefile
> > > > +++ b/sound/pci/ac97/Makefile
> > > > @@ -12,7 +12,7 @@ endif
> > > >  snd-ak4531-codec-objs := ak4531_codec.o
> > > >  
> > > >  # Toplevel Module Dependency
> > > > -obj-$(CONFIG_SND_AC97_CODEC) += snd-ac97-codec.o
> > > > +obj-$(CONFIG_SND_AC97_CODEC) += snd-ac97-codec.o ac97_bus.o
> > > 
> > > Better to keep snd- prefix for ac97_bus module (although it can be
> > > used independently from ALSA)...?  It's an open question.
> > 
> > The idea is to be able to use ALSA as modules and the extra function 
> > driver linked in, or vice versa.  Therefore ac97_bus.o should probably 
> > be selected with its own config symbol allowing for things like:
> > 
> > config UCB1400_TS
> > 	tristate "UCB1400 touchscreen interface"
> > 	select AC97_BUS
> > 
> > 
> > And similarly:
> > 
> > config SND_AC97_CODEC
> > 	...
> > 	select AC97_BUS
> > 
> > This way there is no hard linkage depedency between ALSA and any ad-hoc 
> > codec function driver.
> 
> Yes, I understand the purpose.  My concern was whether we keep a
> consistent module name rule for the modules in sound directory, or
> simply use as it is.  I have no special preference here, and would
> like to hear from others.
> 

We should probably stick with the snd- naming convention because the
ad-hoc bus module does require the sound drivers to be loaded before any
ad-hoc driver will work. This does not mean the sound modules or bus
module needs to be loaded before the ad-hoc driver, it just means the
ad-hoc driver has a functional dependency on the others. 

Liam



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