Re: [PATCH v2 2/2] ASoC: Intel: Skylake: Add Cometlake PCI IDs

[Pierre-Louis Bossart]

On 5/8/19 11:51 AM, Evan Green wrote:
> On Tue, May 7, 2019 at 3:31 PM Pierre-Louis Bossart
> <pierre-louis.bossart@xxxxxxxxxxxxxxx> wrote:
> > On 5/7/19 4:53 PM, Evan Green wrote:
> > > Add PCI IDs for Intel CometLake platforms, which from a software
> > > point of view are extremely similar to Cannonlake platforms.
> >
> > Humm, I have mixed feelings here.
> >
> > Yes the hardware is nearly identical, with the exception of one detail
> > that's not visible to the kernel, but there is no support for DMICs with
> > the Skylake driver w/ HDaudio, and Chrome platforms are only going with
> > SOF, so is it wise to add these two CometLake platforms to the default
> > SND_SOC_INTEL_SKYLAKE selector, which is used by a number of distributions?
> >
> > I don't mind if we add those PCI IDs and people use this driver if they
> > wish to, but it may be time for an explicit opt-in? The
> > SND_SOC_INTEL_SKYLAKE definition should even be pruned to mean SKL, APL,
> > KBL and GLK, and we can add DMI-based quirks for e.g. the Up2 board and
> > GLK Chromebooks which work with SOF.
>
> I don't have the context here, so feel free to ignore me. But it seems
> like such a tiny amount of extra bits to add to make Cometlake work,
> and then there's no hassle for the distributions when Cometlake
> devices start showing up in the wild. So while things are more or less
> the same, why not continue piggypacking off the default?
> Or are you saying that the lack of DMIC support means the default
> should be to use a different driver?

Yes, it's the latter case, SOF will be the only driver supporting DMICs 
on CometLake, so it'd be better to avoid creating a conflict with SOF or 
enabling a configuration by default which is known to have restrictions. 
It's fine to add the CML IDs, but better avoid adding CML under the 
SKYLAKE all-you-can-eat selector.