ALSA: Difference between revisions

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sound.enable = true;

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* on a console fire up alsamixer

* you see plenty of vertical bars?

** you should be okay

* you see very few vertical bars and the sound card (top-left) is something like "PC Speaker"?

** hit the 'S' key, you should be able to switch to the "real" audio card (if not your audio card is likely to not being supported yet).

** when the real audio card is selected you should be viewing the "plenty vertical bars" thing.

*** first thing to do is to disable pc speaker (kernel module "snd-pcsp", see below.

Sometimes the pc-speaker is the default audio card for ALSA. You can make your real sound card default instead.  For example, if your sound card is "hda-intel" then add

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Sometimes, we may want to disable one of intel cards. Here is how to disable first card, but enable the second one.

edit <code>/etc/nixos/configuration.nix</code> and add "snd_pcsp" to <code>boot.blacklistedKernelModules</code> option:

Some hardware specific problems can be resolved by adjusting the options for the sound module. For example, the microphone may be stuck on an unusably low volume. First you should be sure that you have already checked the settings in alsamixer to make sure nothing is muted, and also any physical buttons on your computer (I have twice overlooked the mute button on laptops!).  

You should be able to look up the available options for ''model'' in [https://www.kernel.org/doc/Documentation/sound/hd-audio/models.rst models.rst]. You can try them out interactively as follows:

##: $ lsof /dev/snd/*

##: COMMAND     PID     USER   FD   TYPE DEVICE SIZE/OFF NODE NAME

##: pulseaudi 14080 goibhniu   30u   CHR 116,7     0t0 5169 /dev/snd/controlC0

##: pulseaudi 14080 goibhniu   37u   CHR 116,7     0t0 5169 /dev/snd/controlC0

## Kill them