[alsa-devel] alsactl adds volume controls?

Raymond Yau superquad.vortex2 at gmail.com
Sat Aug 28 00:58:20 CEST 2010

2010/8/28 David Henningsson <david.henningsson at canonical.com>

> 2010-08-27 17:43, Clemens Ladisch skrev:
> > David Henningsson wrote:
> >> So I've discovered that my sound card has a "PCM Playback Volume"
> >> control, but changing that control does not alter the volume.
> >>
> >> Interestingly enough, this control does not come from the HDA parser, it
> >> is added by alsactl at boot time...!
> >
> > This control was created by the software volume plugin.  When not using
> > this plugin, the control does not have any effect.
> >
> > To get rid of it, delete its entry from /etc/asound.state.
> Hmm, I wonder if this is an Ubuntu-specific bug then? Because when I run
> Maverick (the upcoming Ubuntu release) from a Live-CD, the "PCM Playback
> Volume" control is still there (and there is no asound.state, neither in
> /etc or in /var/lib/alsa).
> When I use the plughw interface, the "PCM Playback Volume" does not
> affect volume output. Should I use another device string to test the
> softvol plugin, to see if it's there or not?

The softvol plugin it is defined in "front" device in

reason is some HDA codec does not has any hardware volume control (analog)

this user-defined control only effective when the application use "front"

it is a bug in PA server to open "front" device for playback and capture

it is not easy to remove the control unless you know the trick

shutdown without alsactl store

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