By default there's no sound support in Debian 10 image provided by GCP;
when you run find /lib/modules/$(uname -r) -type f -name '*.ko' | grep snd to list all the loadable modules there are no sound modules whatsovewer.
Additionally when you install alsa-utils and run it you wil see:
wb@deb10:~$ sudo alsactl init
alsactl: init:1757: No soundcards found...
I tried to find a solution but after two hours I gave up in favor of finding a workaround.
If you're OK with Ubuntu 18.04 LTS - then you're in luck - this module is there:
wb@ubuntu18:~$ modinfo snd-aloop
filename: /lib/modules/5.4.0-1063-gcp/kernel/sound/drivers/snd-aloop.ko
license: GPL
description: A loopback soundcard
author: Jaroslav Kysela <[email protected]>
srcversion: 9401A0B894527BA1238B364
depends: snd-pcm,snd
retpoline: Y
intree: Y
name: snd_aloop
vermagic: 5.4.0-1063-gcp SMP mod_unload modversions
signat: PKCS#7
signer:
sig_key:
sig_hashalgo: md4
parm: index:Index value for loopback soundcard. (array of int)
parm: id:ID string for loopback soundcard. (array of charp)
parm: enable:Enable this loopback soundcard. (array of bool)
parm: pcm_substreams:PCM substreams # (1-8) for loopback driver. (array of int)
parm: pcm_notify:Break capture when PCM format/rate/channels changes. (array of int)
and after modprobe snd-aloop we can see it loaded along with all dependencies:
wb@ubuntu18:~$ lsmod | grep snd
Module Size Used by
snd_aloop 24576 0
snd_pcm 102400 1 snd_aloop
snd_timer 36864 1 snd_pcm
snd 86016 3 snd_timer,snd_aloop,snd_pcm
soundcore 16384 1 snd
and if I run
wb@ubuntu18:~$ sudo alsactl init
Found hardware: "Loopback" "Loopback Mixer" "" "" ""
Hardware is initialized using a generic method
We can see that there's some audio "hardware" present.
Module in question is also present "out of the box" in Centos8.
It's missing on the other hand in:
- Debian 10
- Debian 11
- Ubuntu > 20
