[LAU] Alsa setup question

[hollundertee at gmx.net]

I discovered that I sent this message only to Len instead of to the
list. Happens to me far too often...

On Wed, 29 Apr 2015 15:16:24 -0700 (PDT)
Len Ovens <len at ovenwerks.net> wrote:

> > In the very rare occasion that I do need to use pulse, I also start
> > it manually. I have taken all kinds of measures to prevent pulse
> > from starting itself. This question is solely about alsa.  
> 
> Or to put it another way, desktop audio. The tool that does what you
> want is (you probably won't like this) pulseaudio. PA is the only
> tool I know that can switch an application from one output/input to
> another on the fly without stopping the application streaming that
> audio. Learning about Pulse enough to find a way of stopping it from
> playing with IF levels seems to be the solution to the problem.
>
> Almost any other solution would require the restarting of the
> application streaming audio to pick up the new device. PA can move
> the stream to a new device in mid stream. It would still take some
> script I think... probably run by udev, but I am not sure as I have
> my system setup to never do sleep mode... In fact my swap partitions
> are not big enough as they were setup when I had less memory :)  

Right, I did not consider the case of switching a running application
over to the new interface. However, this is a limitation I could live
with. Do you know a solution for that?

It would be sufficient if the default interface was properly set on
boot or resume. It would probably not hurt if it was set whenever a usb
audio device gets plugged in. I'm not quite sure which mechanism allows
me to do that. ALSA alone? Udev?

> PA does not always play with alsa volume levels. It seems to depend
> on the AI itself. For example the ice1712 based cards do not have
> this problem. This says to me that there is probably a profile set up
> for the intel HDA cards that tells PA how to set the volume levels
> and changing the profile could make it so PA was no longer able to do
> so.  

I've seen it mess with the mixer too many times, including turning the
mic volume to max, turning the mic boost to max and nearly ruining my
speakers and my ears. And quite simply: if I set the mixer levels, I
expect them to stay that way.

Regards,
Philipp