More buzzing fun with snd_emu10kx - but now with more determinism!

[Garrett Cooper]

    Getting back to the thread I brought up before (with my now dead
email address):
http://unix.derkeiler.com/Mailing-Lists/FreeBSD/stable/2010-06/msg00036.html
, I now have a more deterministic testcase for this issue.
    The problem appears to be with vchan-related code. If I start up
4+ applications on my machine that access the audio device, all goes
wonky on the 4+ allocation (I was stress testing the nvidia driver to
see whether or not it'd break with multiple instances of vlc, and
stumbled on this by accident). So pushing the number of consumers of
the audio subsystem forces a breakdown somewhere (even though the
number of available hardware vchans is set to 16).
    I'll continue to look into this further as time permits.
Thanks,
-Garrett