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

Tanu Kaskinen tanuk at iki.fi
Mon Sep 19 08:36:05 UTC 2016

On Sun, 2016-09-18 at 17:56 +0530, Nishit Sharma wrote:
> On Sun, Sep 18, 2016 at 5:19 PM, Tanu Kaskinen <tanuk at iki.fi> wrote:
> > On Sat, 2016-09-17 at 17:51 +0530, Nishit Sharma wrote:
> > > 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
>    *Yes AMIC is detected as HeadSet when executed pulseaudio*
>  but then you say that when the headset is plugged in, the port changes
> > 
> > from AMIC
> > to DMIC, which doesn't make sense.
>    * I missed one thing, when i plugged out Headset from target board,
> pulseaudio switches port from AMIC to DMIC*
> *    which i think should initializes ( hw params ) DMIC first as done for
> AMIC??*

No, hw params are not reconfigured. Only mixer settings are changed
according to the UCM configuration.

> > > 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.
> *   If it is so then DMIC will be accepting HW params which were set for
> AMIC ( HeadSet ), but then there will be difference between the period
> size, buffer size passed to DMIC sink which **again can cause problem? *

Why would there be a difference in the buffer parameters? Since we
don't reconfigure the hw params, it's clear that there will be no

If you actually want different buffering parameters depending on the
active port, that's not supported in pulseaudio.

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mailing lists rather than using HTML formatting. The formatting will be
lost anyway in replies, and the list archive also strips the


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