#889294 alsa-utils: External mic via combo jack is not detected on Acer Aspire V3-372

Package:
alsa-utils
Source:
alsa-utils
Description:
Utilities for configuring and using ALSA
Submitter:
Vladimir Kudrya
Date:
2021-01-21 20:51:03 UTC
Severity:
normal
#889294#5
Date:
2018-02-03 13:39:57 UTC
From:
To:
Dear Maintainer, I have Acer Aspire V3-372 laptop with ALC255 sound card.
It has a single combo jack for stereo out + mic. Everything works except
external mic.
Mixser has only single input channel for mic. Switching "Auto-Mute mode"
does not affect the mic.

I tried some workarounds, like setting model=dell-headset-multi parameter
for snd_hda_intel module. This adds another channel for external mic, but
also some channels that are not present on the laptop, jack sense becomes
broken, and the external mic is very quiet, although working.

I also tried hdajackretask and found out that external mic is physically
located on the port 0x19.

Digging here https://patchwork.kernel.org/patch/9596691/ I found supposedly
working configuration for the port and tried to apply it:

    $ echo "0x19" "0x01a1913c" | sudo tee /sys/class/sound/hwC0D0/user_pin_configs
    0x19 0x01a1913c
    $ echo 1 | sudo tee /sys/class/sound/hwC0D0/reconfig
    1

This yielded the best solution so far, but still unworkable. No extra
non-existent channels, external mic is accessible through a separate mixer
channel, but jack sense breaks, and the mic is very quiet.

Attached some info on the card from sysfs.
#889294#10
Date:
2021-01-21 11:21:20 UTC
From:
To:
Seems to be fully fixed by adding:

    options snd_hda_intel model=alc255-acer

to a file in /etc/modrobe.d/

If there is a mechanism for assigning this model automatically based on dmi data, it might be a good idea to apply it.
#889294#15
Date:
2021-01-21 20:10:19 UTC
From:
To:
...but now analog-output-speaker port in pulseaudio has "availability unknown" when jack is unplugged. This prevents auto fallback when unplugging jack.
When jack is plugged in, analog-output-speaker is correctly "not available".

analog-input-internal-mic always has "availability unknown"
analog-input-headset-mic is correctly "not available" when jack is unplugged, but "availability unknown" when plugged in.
#889294#20
Date:
2021-01-21 20:22:57 UTC
From:
To:
Upgraded to pulseaudio 14.2 from unstable.

analog-output-speaker and analog-output-headphones now mutually trading between "availability unknown" and "not available" on jack state. At least auto switching now works for output.

How does pulseaudio determine "availability" and how to affect it?
#889294#25
Date:
2021-01-21 20:46:36 UTC
From:
To:
model=aspire-headset-mic has similar effect.