More Generic Audio Graph Sound Card idea

[Sameer Pujar]

Hi Morimoto-san,

On 8/24/2020 5:55 AM, Kuninori Morimoto wrote:
> External email: Use caution opening links or attachments
>
>
> Hi Mark
> Cc Sameer
>
>> Having an audio-graph-card2 isn't ideal but may be required at least
>> during development :/  Ideally we'd be able to have the new driver parse
>> both binding formats (or rather, have the new binding format be new use
>> cases for the same binding format) and only use -card2 while it's in
>> development.
> If you want to update current audio-graph-card without creating new
> audio-graph-card2, I'm OK about it. But need adjusting / agreement.
>
> Current audio-graph-card "DSP" user is only me, and I'm using it only locally.
> Thus upstream doesn't get damage if I removed "audio-graph-scu-card"
> (= DSP use case) support.

> OTOH, Sameer is posting patch for "-cc-" support. If it was accepted
> and he used it on upstream (= on tegra),
> keeping compatibility will be very difficult and/or code will be very confusable.
>
> If Sameer can OK and wait new audio-graph-card, maybe we have no compatibility issue.
> But in such case, 1st version of new audio-graph-card might be not enough for him.
> Sameer need to waiting / testing / adjusting / etc, etc...

The series [0] introduces small deltas to resolve issues I am facing. As 
you see, most of the implementation is unchanged for the graph-card 
driver. Hence I am not sure if we need a new driver now. If at all it 
gets complicated in future, the "-cc-" compatible can be moved to new 
driver? Please note that the new "-cc-" compatibility is added to 
address following and some of these are discussed in [1].
- DPCM usage with component model (where there can be N number of 
components available and M (<= N) of them can be connected together to 
form an audio path). For example the path would be like,
FE -> BE_1 -> BE_2 -> ... -> BE_M.
- I am extending dpcm_path_get() for this reason and DAI ops get called 
for all connected components.

[0] https://lkml.org/lkml/2020/8/5/42
[1] https://lkml.org/lkml/2020/4/30/519
>
> Thank you for your help !!
>
> Best regards
> ---
> Kuninori Morimoto