[SOLVED] Static noise when no sound

greeenstone · 2022-02-20 01:22:35

Hello everyone. This is my very first post ever, so I will try my best

Goal

Make constant noise go away (which appears when nothing "plays" for about 6 sec)

Setting:

- Gnome DE
- Pipewire (pulseaudio and Jack completely deleted)
- Select sof sound-driver by "options snd-intel-dspcfg dsp_driver=2" (so we use "snd_soc_skl" instead of "snd_hda_intel") in "/etc/modprobe.d/sound.conf" to fix microphone (and setting alsa topology) according to this (mic is working now)
NOTE: for the sof-sound-driver there are no options aviable like "options snd-hda-intel power_save=0"

Suspicion:

noise is due to soundcard turning into power-saving mode (default time for going to power-save-mode are 5 sec and I observe the noise after 6 seconds)

What I tried:

- mute microphone
- dis-/enable automute in alsamixer

with pipewire-media-session
Turn "node.pause-on-idle = false" and "session.suspend-timeout-seconds = 0" in "/usr/share/pipewire/media-session.d/alsa-monitor.conf" in case that is the wrong location:

sudo mkdir -p /etc/pipewire/media-session.d/
sudo cp /usr/share/pipewire/media-session.d/alsa-monitor.conf /etc/pipewire/media-session.d/

with wireplumber basically doing the same:

sudo cp -a /usr/share/wireplumber/main.lua.d/50-alsa-config.lua /etc/wireplumber/main.lua.d/50-alsa-config.lua
sudo nano /etc/wireplumber/main.lua.d/50-alsa-config.lua
## edit:
    --["node.pause-on-idle"]     = false,
    --["session.suspend-timeout-seconds"] = 0, 
reboot
systemctl --user restart wireplumber

What can I do?
Many thanks in advance

Last edited by greeenstone (2022-02-20 18:29:47)

V1del · 2022-02-20 10:21:14

Good general investigation, modinfo'ing through the various modules related to snd-soc shows that snd-soc-core has a pmdown_time param.

Therefore try a

options snd_soc_core pmdown_time=0

Last edited by V1del (2022-02-20 10:26:52)

greeenstone · 2022-02-20 11:32:57

Thanks for your reply

I assumed that I need to change the option in "/etc/modeprobe.d/sound.conf". However, this was with no effect. I also tried setting the parameter to "-1" and to type "snd_soc_skl" (all such combinations).

Note, that if I open the gnome-settings and enter the sound tab, the noise instantly stops. Would it be possible to set up a low-cpu process that starts as the system boots and keeps the soundcard busy? If so, how?

V1del · 2022-02-20 11:44:21

Sanity check because it gets often forgotten, you did reboot after setting this right? And if I'm interpreting upstream/the docs correctly setting it to 0 is the only sensible value for disabling.
If you did, see this thread where someone had to do something similar: https://bbs.archlinux.org/viewtopic.php?id=256658 note the initial post for how such a service might look and the second for how to set it up for the user session rather than system wide.

Last edited by V1del (2022-02-20 11:50:10)

greeenstone · 2022-02-20 13:57:11

Indeed, I rebooted after each change.
I followed this guide and it worked. But I did not managed to run it with the system-boot (the silly noise is still present during the login-screen)
creating the *.service file in "/etc/systemd/system" wasn't sufficient. Anything else I have to adapt?

Last edited by greeenstone (2022-02-20 13:57:39)

V1del · 2022-02-21 01:31:37

it is an user service as it depends on things that are only properly set up once you log in. I don't see this as easily trivially solvable for just the login screen. as you'd have to stop it once the login screen has finished to let the user session access the device. you might be able to do this with some scripting capabilities of whatever DM you're using

Arch Linux

#1 2022-02-20 01:22:35