I just upgraded a notebook to a fresh Debian 11 system (I started the
system with Debian testing +/- a year ago).
The notebook device is a Lenovo Thinkpad 13S. A year ago, I turned the
dsp_driver on to work-around the firmware-sof package not having been
provided in Debian back then:
```
cat /etc/modprobe.d/no-sof.conf
# play sound without the SOF firmware
options snd_intel_dspcfg dsp_driver=1
```
One complaint of the customer who owns the notebooks then was, that
the internal microphone was not usable with those machines.
Today, I looked at switching to using the SOF firmware with the
snd_hda_intel driver and disable the fallback DSP driver again:
```
cat /etc/modprobe.d/with-sof.conf
# play sound without the SOF firmware (this is the kernel's default)
options snd_intel_dspcfg dsp_driver=0
```
With SOF, I was able to see the onboard DMIC microphone, but the
microphone does not have any input signal. (And yes, I know how to
enable/use microphones on computer, with and without pulseaudio).
I then found a post on the SOF project's upstream bug tracker, that
provided me with a work-around solution and I wonder if the related
fix might be a bullseye-pu upload candidate:
The work-around is presented here:
https://github.com/thesofproject/linux/issues/2460#issuecomment-779212719
In a nutshell, a binary blob is offered there to replace the file
sof-hda-generic-2ch.tplg in firmware-sof-signed.
After a reboot, with that firmware file replaced, the onboard DMIC
works and has become usable.
The related upstream PR is:
https://github.com/thesofproject/sof/pull/3847
The PR never got applied, as it got closed when upstream's master
branch got renamed to "main". Noone ever cared for reopening that PR.
To clarify the situation, I pinged the PR submitter and upstream via:
https://github.com/thesofproject/linux/issues/2460#issuecomment-898423772
It would be awesome to get a fixed firmware-sof version (which then
also works for the Lenovo Thinkpad 13S) into Debian 11.1. Let me know
if I can assist with anything around fixing this bug. Thanks.
Thanks+Greets,
Mike