Re: [PATCH v4] ASoC: amd: yc: Fix non-functional mic on Lenovo 82YM

[Mario Limonciello]

On 10/2/2023 09:13, Linux regression tracking (Thorsten Leemhuis) wrote:
> On 02.10.23 15:47, Mario Limonciello wrote:
> > On 10/2/2023 06:52, Mark Brown wrote:
> > > On Mon, Oct 02, 2023 at 11:32:48AM +0200, Linux regression tracking
> > > (Thorsten Leemhuis) wrote:
> > >
> > > > Makes me wonder: How many more such quirk entries will be needed? Will
> > > > we have all machines listed soon, or do we expect that future Lenovo
> > > > hardware will need entries as well? If it's the latter: are quirks
> > > > really the right solution here, or do they just hide some bug or then
> > > > need for code that automatically handles things?
> > >
> > > x86 firmware descriptions are terrible, it's just an endless procession
> > > of quirks.  The model for ACPI is not to describe key information in the
> > > kernel and instead on Windows load device specific information from
> > > separately supplied tables.  On Linux that translates into these endless
> > > quirks, on Windows it's platform specific drivers for otherwise generic
> > > audio hardware.
> >
> > I knew there was a TON of "82" prefix systems from Lenovo so it was an
> > educated guess that all of them needed DMIC support.  This was incorrect
> > because one of them didn't have DMIC and that caused a no mic support
> > problem on that system.
> >
> > So in the case of this seemingly endless list of systems being added to
> > enable DMIC support Mark is right, Windows does it differently.
>
> Now I understand things better, many thx. But please allow me one more
> question from the cheap seats:
>
> Seems before c008323fe361 things worked for a lot of systems for about
> one year thx to 2232b2dd8cd4 (which added the wide "82" prefix quirk).
> We then made that one machine work with c008323fe361, but broke a lot of
> others with it that now need to be fixed with additional quirks; that
> "TON of 82 prefix systems" sounds like we might not be close to the end
> of that journey.
>
> So can't we just do it the other way around and assume DMIC support on
> Lenovo 82* machines, except on those where we know it to cause trouble?
>
> Again: you are the experts here. If you are positive that we soon got
> all machines covered where c008323fe361 causes a regression, then I
> guess it's best to continue the patch we're on.

I don't like lists that enable something for a ton of systems and then 
lists that disable something for a subset of them.  This becomes 
difficult to maintain.

I'm not positive, but the only way we get a full list is from Lenovo.

> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> --
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