[Pkg-pulseaudio-devel] Bug#519705: looks like pulseaudio modules try exclusive access on alsa devices

[Niels Böhm]

This heavily looks like /usr/lib/pulse-0.9/modules/module-alsa-sink.so (and 
probably other pulseaudio modules, but I don't know about the correct 
access policy of alsa devices and the scope of the pulseaudio modules) try 
to obtain exclusive access to an alsa device via "hw:" instead of "plughw:" 
and consequently either lock out other apps going directly through alsa 
from accessing the sound device or being unable to arbitrate the device 
itself in case it is already in use by another app when pulseaudio starts 
up.

AFAIRC, this is true for sound cards/drivers that don't have the intrinsic 
capability to consume several audio streams at once and must use software 
mixing (hence in theory, "plughw:" should work, since alsa provides the 
software mixing then).

Also, #521675 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521675 and 
#521282 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521282 might be 
related to that issue.


Regards,
Niels Böhm