Following upstream (and Ubuntu) directions, I've been able to improve PulseAudio ALSA plugin in a way that it eventually works fine with applications using PA directly.
A simple use case: watch a YT video with <your fav. browser> (thus using flash nsplugin) while listening to music with Audacious2 or Amarok. With the current setup, this causes the nsplugin to take over sound devices completely, since alsa is not properly configured to use PA when available.
Created attachment 222863 [details, diff]
Created attachment 222865 [details]
Created attachment 222867 [details]
Note: pulse.conf contains absolute path to PA alsa lib because its dirname is not in ld.so.conf nor in ALSA stuff using it (upstream bug or feature?). Ubuntu uses to place a ld.so.conf entry to address this issue, by the way.
ALSA team? Can I merge the patches?
This bug is rotting! Please do something.
Since nobody is responding here, I did it myself.
+*alsa-plugins-1.0.23-r1 (28 May 2010)
+ 28 May 2010; Fabio Erculiani <email@example.com>
+ -alsa-plugins-1.0.23.ebuild, +alsa-plugins-1.0.23-r1.ebuild,
+ +files/pulse.conf, +files/pulse-alsa.conf:
+ inject default working pulseaudio configuration, close bug #308697