Sound intermittently stops working

[Conrad J. Sabatier]

Anyone have any clues as to what might cause sound to suddenly stop
working?  Every so often, for no apparent reason, my audio output just
stops abruptly and cannot be restored without a reboot.  No error
messages from either the kernel or whatever audio app I may be running
at the time (which will continue playing, blissfully unaware that
anything out of the ordinary is happening).  For all outward appearances
(other than aurally), everything seems to still be working perfectly
normally.

# uname -a
FreeBSD serene.no-ip.org 10.0-CURRENT FreeBSD 10.0-CURRENT #1: Sun Jan
1 18:03:55 CST 2012
conrads at serene.no-ip.org:/usr/obj/usr/src/sys/CUSTOM  amd64

# cat /dev/sndstat
FreeBSD Audio Driver (newpcm: 64bit 2009061500/amd64)
Installed devices:
pcm0: <HDA Realtek ALC888 PCM #0 Analog> (play/rec) default
pcm1: <HDA Realtek ALC888 PCM #1 Analog> (play/rec)
pcm2: <HDA Realtek ALC888 PCM #2 Digital> (play)
pcm3: <HDA Realtek ALC888 PCM #3 Digital> (play)

Sorry I don't have any more useful diagnostic-type information.

Does anyone else ever experience this sort of thing?  Is there any way
to get the sound going again, other than rebooting?

Thanks!

-- 
Conrad J. Sabatier
conrads at cox.net