[pulseaudio-discuss] Endpoints switching rules

Tanu Kaskinen tanuk at iki.fi
Sat Dec 10 13:37:23 UTC 2016

On Thu, 2016-12-08 at 15:43 +0530, Nishit Sharma wrote:
> On Thu, Dec 8, 2016 at 3:37 PM, Tanu Kaskinen <tanuk at iki.fi> wrote:
> > On Thu, 2016-12-08 at 15:28 +0530, Nishit Sharma wrote:
> > > Hi All,
> > > 
> > > I am facing noise issues when playing through Speaker/Headphone using
> > > pulseaduio and UCM config files but this is not happening in case of
> > > normal alsa_play.
> > 
> > What kind of noise issues? And what is "normal alsa_play"? Do you mean
> > aplay?
> It's like when song played with too much volume which speaker can
> handle, like if we raises volume to max limits. Yes,it's aplay

Ok, that's a bit weird. You said that the volumes in alsamixer were the
same with and without pulseaudio - how did you check? Did you run
"amixer --card=broxtonrt298" and ran it through diff?

If the mixer settings really are the same, then check that no volumes
in pulseaudio are over 100%. You can check that with "pactl list sinks"
and "pactl list sink-inputs" while you're playing the test file.

Also check the sink and sink input rates. If they are different,
pulseaudio will do resampling, which shouldn't cause this kind of
issues, but it's worth checking if playing a file that matches the sink
sample rate makes the problem go away.

Lastly, you could check if there are differences in the parameters that
aplay and pulseaudio set (like sample rate or sample format). Maybe the
hardware doesn't work properly with certain formats. I've heard of one
instance where hardware made some noise with normal 16-bit audio, while
24-bit audio played cleanly, even though the audio file was 16-bit in
both cases. When you play audio, you can check the current hardware
parameters with "cat /proc/asound/card0/pcm0p/sub0/hw_params". Or at
least that works with HDA, I'm not sure if that's an universal
interface that works with all kernel drivers.



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