Comment 17 for bug 1912052

I've made a new test, currently on POPOS 21.04, kernel 5.13:

❱ uname -rv
5.13.0-7614-generic #14~1631647151~21.04~930e87c-Ubuntu SMP Fri Sep 17 00:24:58 UTC

1) default boot options:
========================
- internal mic works, external not

2) changed to intel_dspcfg.dsp_driver + headset-mic:
========================
❱ cat /proc/cmdline
initrd=\EFI\Pop_OS-a99686bf-c48a-464b-af3a-25f67847049a\initrd.img root=UUID=a99686bf-c48a-464b-af3a-25f67847049a ro snd_intel_dspcfg.dsp_driver=1 snd_hda_intel.model=headset-mic

- neither mic works

3) changed to intel_dspcfg.dsp_driver + alc255-acer
=========================
❱ cat /proc/cmdline
initrd=\EFI\Pop_OS-a99686bf-c48a-464b-af3a-25f67847049a\initrd.img root=UUID=a99686bf-c48a-464b-af3a-25f67847049a ro quiet splash snd_intel_dspcfg.dsp_driver=1 snd_hda_intel.model=alc255-acer

- external mic is now working (!), when jack is plugged-in, it corerctly asks what device have I connected (headset or headphones?)
- internal mic is not working, though :(

4) it (does not) works with pci=nocrs, too:
================================
❱ cat /proc/cmdline
initrd=\EFI\Pop_OS-a99686bf-c48a-464b-af3a-25f67847049a\initrd.img root=UUID=a99686bf-c48a-464b-af3a-25f67847049a ro quiet splash pci=nocrs snd_intel_dspcfg.dsp_driver=1 snd_hda_intel.model=alc255-acer

So, this solution is not very practical, because when I do not have headset available at the moment, I cannot use internal microphone :(