the original ad-audiomp branch notes:
Add MP locking to the audio drivers.
Making the audio drivers MP safe is necessary before efforts
can be made to make the VM system MP safe.
The are two locks per device instance, an ISR lock and
a character device lock. The ISR lock replaces calls to
splaudio()/splx(), and will be held across calls to device
methods which were called at splaudio() before (e.g.
trigger_output). The character device lock is held across
calls to nearly all of the methods, excluding some only
used for initialization, e.g. get_locks.
Welcome to 5.99.57.
via the standard audio interfaces is redirected back to userland as raw
PCM data on /dev/padN.
One example usage is to stream audio to an AirTunes compatible device using
rtunes (http://www.nazgul.ch/dev_rtunes.html), ie:
$ rtunes - < /dev/pad0
$ mpg123 -a /dev/sound1 blah.mp3
Another option is to capture audio output from eg. Real Player, by simply
instructing Real Player to output to /dev/sound1, and running:
$ cat /dev/pad0 > blah.pcm
