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

[Felipe Tonello]

Hi Arun,

On Mon, Aug 5, 2013 at 8:43 PM, Arun Raghavan
<arun.raghavan at collabora.co.uk> wrote:
> 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).

I will probably need this use case. I hope to send a patch in a few
weeks to come.

>
>> 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.

Actually I realized was probably a problem in my UCM configuration.
Now it seems to be ok.

>
>> 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.

I saw your patch. It was not upstreamed right? Also, how would you set
that flag in run-time?

>
> 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).

Do you have more information about that? Because here I have control
over the kernel, so we could implement there if needed.

Regards,
Felipe Tonello