Re: [RFC PATCH 03/14] ASoC: qcom: Add USB backend ASoC driver for Q6

Wesley Cheng
2022-12-27T21:11:04Z

Hi Mark/Greg,

On 12/27/2022 7:11 AM, Mark Brown wrote:
> On Tue, Dec 27, 2022 at 02:45:13PM +0100, Greg KH wrote:
>> On Tue, Dec 27, 2022 at 01:04:55PM +0000, Mark Brown wrote:
>>> On Sat, Dec 24, 2022 at 10:02:59AM +0100, Greg KH wrote:
>
>>>>> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
>
>>>> All of the code in this patch series is older than 2022 as I know it has
>>>> been in shipping devices for many years. Please use the proper
>>>> copyright year to make your lawyers happy...
>
>>> Are you *positive* about this. Based on some preparatory discussions
>>> the Qualcomm people had with Takashi and I it seemed like this was a new
>>> version of existing concepts. I'm sure they had something already but
>>> it's not obvious to me that they're just posting the same code.
>
>> I thought that this same code has been shipping in devices for a few
>> years now in the last few Samsung phone models. Is this not the same
>> code that is in those devices?
>
>> If not, why not, what happened to that codebase that makes it not worthy
>> of being submitted upstream?
>
> I don't specifically know anything about that code but I'd expect that
> for out of tree code breaking new ground like this there'd be a strong
> likelyhood that there'd be design level issues and that's what the pre
> submission discussions were all about - how to fit the concept into the
> kernel subsystems in a way that might be maintainable. There's also
> been the whole transition to their new DSP firmware going on. It's
> possible that what was shipped was implemented in the same way with the
> same code but I'd not assume that this is the case without actually
> comparing the two.

It's correct that all the ASoC related patches are new, and didn't exist
previously in QC products. It is due to the fact that Android has a
different ALSA userspace concept which allowed for a lot of the Q6 audio
front end (AFE) communication to be done from userspace, I believe.
This is the reason that we had to introduce this new ASoC based design.

I can't comment much more about the Android ALSA design, maybe @Patrick
Lai can.

Thanks
Wesley Cheng