[alsa-devel] [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 at linux.intel.com> 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.