[alsa-devel] [PATCH v4 1/7] ASoC: hda - add ASoC HDA codec match function

[Takashi Iwai]

At Tue, 26 May 2015 14:32:56 +0100,
Mark Brown wrote:
> 
> On Tue, May 26, 2015 at 07:24:03AM +0200, Takashi Iwai wrote:
> > Mark Brown wrote:
> > > On Mon, May 25, 2015 at 01:55:59PM +0200, Takashi Iwai wrote:
> 
> > > > Once when we get the common criteria for matching (both for asoc and
> > > > legacy), we can move to the unified match method.
> 
> > > I really don't understand this idea that we need to work out what the
> > > common criteria for matching are, HDA is an enumerable bus isn't it?
> 
> > The common match method *does* exist.  It's just shifted to two parts,
> > one for ASoC and one for legacy, because of two different objects.
> 
> What are these objects supposed to be then and why does the bus for HDA
> CODECs know about the differences between them?  They're both called HDA
> CODECs which might lead one to think that they are supposed to represent
> the same thing.

Both legacy and ASoC drivers contain own codec drivers, but their
classes inherit the same HD-audio core object class that is managed by
HD-audio core bus.  Meanwhile, since the id table is (still) not
embedded into HD-audio core object, the match method is still placed
in each (asoc and legacy) driver core code.

> > > I'm also wondering how this interacts with the Tegra HDA device by the
> > > way...
> 
> > It's a part of HDA legacy.  No difference from any other HDA devices.
> > What's the problem with Tegra?
> 
> People keep talking about PCI as being a differentator here, though
> apparently the Intel systems are all PCI so perhaps not.

Yeah, Tegra also hits this whole movement.  Or better to say, the
whole HD-audio picture has been rewritten, and the transition about
Tegra was already finished.  For the legacy HDA, the rest are rather
about the codec side.


Takashi