[pulseaudio-discuss] PA UCM support (Volume and Jack)

[Arun Raghavan]

On Mon, 2013-08-05 at 11:43 -0700, Felipe Tonello wrote:
> Hi all,
> 
> I'm using UCM configurations to handle multiple devices and
> playback/capture mixer controls. It seems that PA UCM implementation
> just store the PlaybackVolume PlaybackSwitch properties but doesn't
> make any usage of it.
> 
> What I want to do is basically to be able to change hardware volume
> instead of just software volume. When I plug a Headphone, for
> instance, I want PA to change the volume of the alsa control that I
> specified by PlaybackVolume in the UCM file not just the sink volume.
> 
> Is that possible to do? Does it require a patch or some work?

It is possible of course, but hasn't been implemented (yet).

> Also, jack support for UCM seems to have a bug. For when using UCM
> support, when I start PA or change a card profile with a jack
> previously plugged, it doesn't recognizes that unless I unplug and
> plug again.

David was looking into hooking up jack detection with UCM, so might have
some more useful information for you.

> Any comments on that as well?
> 
> OBS: I'm using PA 3.0.

You'd also mentioned the problem with modem PCMs on IRC. I think we
really don't have much choice here but to go with the
PA_SINK_ALWAYS_RUNNING flag that I'd posted earlier, coupled with adding
a field in the UCM to signal that this needs to be set.

Yes, we would ideally like for these paths to be set up in the kernel,
but pragmatically, that seems to be quite unlikely to happen on the
Android kernels (at least it hasn't in the last year and a half).

-- Arun