[Sound-open-firmware] amixer pipeline issues

[Daniel Baluta]

Hi Pierre,

We are experiencing issues using  mixer piplines. I think it is the same issue
mentioned here:

https://github.com/thesofproject/sof/issues/3171

We get the issue for all formats: S{16|24|32}_LE

At some point aplay stops with I/O write error.

This PR: https://github.com/plbossart/sof/commit/baed1f0283f190e319444d06cdfc7f7c78afc8b1
doesn't fix the issues as it seems it does for Intel.

We are investigating and suspecting it might be a wild scheduling issue, anyway
I have a generic question about this scenario. Looking at sof-cht-max98090.m4
we have 3 pipelines involved in the playback:

-> [pipeline 1] -> playback DAI using 2 periods
-> [pipeline 3] -> playback pipeline 3 on PCM 0 with 1ms deadline
-> [pipeline 4] -> playback pipeline 4 on PCM 1 with 10ms deadline.

The question is why pipeline 3 and pipeline 4 are not symmetrical, meaning
that they should have the same period size. But one has 1ms and the other
one has 10ms.

What's the idea behind this?