[pulseaudio-discuss] Overrun in Pulseaudio8.0 when switching endpoints

Tanu Kaskinen tanuk at iki.fi
Sun Sep 18 11:49:36 UTC 2016

On Sat, 2016-09-17 at 17:51 +0530, Nishit Sharma wrote:
> Hi All,
> I have observed strange behavior of PulseAudio8.0 which is as:-
> I have one card which have 2 devices AMIC and DMIC. I am using ALSA, UCM
> config files with PulseAudio. Before pulseaudio boots up Headset and DMIC
> have been connected on card.

What does "connected on card" mean?

> When PulseAudio boots up it initializes AMIC (
> Headset ) only and i can record using it.
> Now, the problem starts. When i plugged Headset the Port switching done
> from AMIC to DMIC and after sometime i got overrun without recording
> anything.

You seem to be saying that AMIC is the same thing as Headset, but then
you say that when the headset is plugged in, the port changes from AMIC
to DMIC, which doesn't make sense. Why would the port change away from
the headset when the headset is plugged in? Did you mix up AMIC and
DMIC at some point in your description?

> My analysis:- PulseAudio should initialize both AMIC and DMIC ( setting hw
> params and other stuff ) but only AMIC initialized. Only port switching
> should not have been happened as no hw params setup for DMIC. Port switched
> but PulseAudio is expecting I/P for AMIC. Am i right here?

Hw params are set when opening the PCM device. If AMIC and DMIC are on
the same PCM device, there's no need to reconfigure the hw params (or
if the hardware requires such reconfiguration, pulseaudio certainly
won't do it). It's a bit unclear unclear whether AMIC and DMIC are on
same or different PCM devices, but if they are two ports on the same
sink, then they are on the same PCM device.

I have no idea what you mean by "I/P".


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