[pulseaudio-discuss] Volume controller redirection

Tanu Kaskinen tanuk at iki.fi
Mon Feb 4 15:35:55 PST 2008

On Mon, Feb 04, 2008 at 11:24:48PM +0100, David Kågedal wrote:
> 1) The volume knob will control the main mixer in the GNOME settings,
>    i.e. the same as the volume buttons on the laptop. This means that
>    unless I reconfigure it, it will control the volume of the internal
>    speakers instead of the external speakers that are connected to
>    it. I can reconfigure gnome so that both volume controllers control
>    the Xmod volume instead.
>    Does anyone know if there is a way to make each volume controller
>    control different mixers?

My guess is that both the laptop volume control and Xmod
send keyboard events. If that is correct, then you can check
what keycodes they send with xev.

Run xev in a terminal, and then make sure that the window
that pops up has focus and that you can still see the
terminal output. Pressing keys should cause KeyPress and and
KeyRelease events. Check the keycode values of the volume
controls; if they have the same keycode, I think there's no
way you could control different things with the laptop
controls and the Xmod controls.

If they do send keyboard events and they have different
keycodes, I think you have hope, but I don't know how to do
the configuration...

> 2) When I control the volume of the Xmod, the volume jumps up and down
>    rather erratically, and loses synch between the right and left
>    channel. But this happens when using ALSA directly, so it's not
>    related to PA.

If you control the volume with "alsamixer -c1" (I'm assuming
the card has index 1, you can check that with "cat
/proc/asound/cards"), and it doesn't work any better, then I
think you can't do anything about this problem. If it does
work better, then again you probably can do something, but I
don't know what ;)

Tanu Kaskinen

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