Alsamixer broken in nixos-unstable

[engblom]

Alsamixer is broken after recent changes to nixos-unstable:

$ alsamixer 
ALSA lib control.c:1464:(snd_ctl_open_conf) Unknown field libs
cannot open mixer: Invalid argument

$ nix-shell -p nix-info --run "nix-info -m"
this path will be fetched (0.06 MiB download, 0.30 MiB unpacked):
  /nix/store/fwjba5s3bxmm68m19rks3gv5fajz6d37-bash-interactive-5.1-p12-dev
copying path '/nix/store/fwjba5s3bxmm68m19rks3gv5fajz6d37-bash-interactive-5.1-p12-dev' from 'https://cache.nixos.org'...
 - system: `"x86_64-linux"`
 - host os: `Linux 5.10.93, NixOS, 22.05 (Quokka)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.5.1`
 - channels(root): `"nixos-22.05pre349657.5bb20f9dc70"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[nrdsp]

Getting the exact same issue, on the 5.10.94 kernel:

~ » nix-shell -p nix-info --run "nix-info -m"
this path will be fetched (0.06 MiB download, 0.30 MiB unpacked):
  /nix/store/fwjba5s3bxmm68m19rks3gv5fajz6d37-bash-interactive-5.1-p12-dev
copying path '/nix/store/fwjba5s3bxmm68m19rks3gv5fajz6d37-bash-interactive-5.1-p12-dev' from 'https://cache.nixos.org'...
  - system: `"x86_64-linux"`
  - host os: `Linux 5.10.94, NixOS, 22.05 (Quokka)`
  - multi-user?: `yes`
  - sandbox: `yes`
  - version: `nix-env (Nix) 2.5.1`
  - channels(****): `"home-manager"`
  - channels(root): `"nixos-22.05pre349234.945ec499041"`
  - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[dtzWill]

Welp after diving through alsa sources ("how did this ever work??" etc.), finally figured out it's related to a patch we removed (and more to the story).

See: #157352 for a proposed fix.

#154276 is where the patch was removed, but didn't remove the bits that relied upon setting "libs." in asoundrc (search our tree for libs. to see what I mean-- the PR above removes them for pulseaudio and other places (pulse, jack, pipewire, I think)).

Hmm.

[nrdsp]

Although this doesn't go for the root issue, which @dtzWill addresses above, if you're using PipeWire there's a simple solution which is to disable Alsa altogether. If all you want is to hear your laptop's soundspeakers and control your audio again, which in my case is done with amixer, the following configuration should work fine:

services.pipewire = {
    enable = true;
    alsa = {
        enable = false;
    };
};

[ppom0]

Related to #158474

[flokli]

Is this fixed by #157631?

[flokli]

#157631 did indeed fix this, but it was merged to staging (and still needs to trickle into master)

[rnhmjoj]

For tracking the progress: https://nixpk.gs/pr-tracker.html?pr=157631

[flokli]

This has ended up in master and nixos-unstable, closing.