Sound doesn't work

[Justin R. Smith]

My profile:

FreeBSD jsmith.org 5.3-STABLE FreeBSD 5.3-STABLE #0: Mon Jan 17 11:14:19 
EST 2005     jsmith at jsmith.org:/usr/obj/usr/src/sys/MYKERNEL  i386


Sound worked perfectly in 5.3-release. After upgrading to the stable 
release, it stopped working.

Output of sndstat (with maximum verbosity):

FreeBSD Audio Driver (newpcm)
Installed devices:
pcm0: <CMedia CMI8738> at io 0xa800 irq 17 kld snd_cmi (1p/1r/0v 
channels duplex
 default)
        [pcm0:play:0]: spd 44100, fmt 0x10000010, flags 0x00000000, 
0x00000000
        interrupts 0, underruns 0, ready 0
        {userland} -> feeder_root(0x10000010) -> {hardware}
        [pcm0:record:0]: spd 0, fmt 0x00000000/0x00000008, flags 
0x00000000, 0x00000000
        interrupts 0, overruns 0, hfree 16384, sfree 0
        {hardware} -> feeder_root(0x00000000) -> {userland}

File Versions:
$FreeBSD: src/sys/dev/sound/pci/cmi.c,v 1.29 2004/07/16 03:59:27 
tanimura Exp $
$FreeBSD: src/sys/dev/sound/isa/sndbuf_dma.c,v 1.2 2003/09/07 16:28:02 
cg Exp $
$FreeBSD: src/sys/dev/sound/pcm/vchan.c,v 1.16 2004/01/28 08:02:15 
truckman Exp
$
$FreeBSD: src/sys/dev/sound/pcm/sound.c,v 1.92 2004/07/16 03:59:09 
tanimura Exp
$
$FreeBSD: src/sys/dev/sound/pcm/sndstat.c,v 1.17.2.1 2004/09/14 06:43:46 
truckma
n Exp $
$FreeBSD: src/sys/dev/sound/pcm/mixer.c,v 1.40 2004/06/25 16:34:33 josef 
Exp $
$FreeBSD: src/sys/dev/sound/pcm/feeder_rate.c,v 1.10 2003/04/20 17:08:56 
orion E
xp $
$FreeBSD: src/sys/dev/sound/pcm/feeder_fmt.c,v 1.13 2003/09/07 16:28:03 
cg Exp $
$FreeBSD: src/sys/dev/sound/pcm/feeder.c,v 1.32 2003/09/07 16:28:03 cg Exp $
$FreeBSD: src/sys/dev/sound/pcm/fake.c,v 1.13 2003/09/07 16:28:03 cg Exp $
$FreeBSD: src/sys/dev/sound/pcm/dsp.c,v 1.77 2004/07/02 15:31:44 
netchild Exp $
$FreeBSD: src/sys/dev/sound/pcm/channel.c,v 1.97 2004/02/28 19:47:02 
truckman Ex
p $
$FreeBSD: src/sys/dev/sound/pcm/buffer.c,v 1.23.2.1 2004/11/23 07:13:33 
yongari
Exp $
$FreeBSD: src/sys/dev/sound/pcm/ac97_patch.c,v 1.2 2003/08/21 15:44:55 
orion Exp
 $
$FreeBSD: src/sys/dev/sound/pcm/ac97.c,v 1.51 2004/05/08 03:41:40 sanpei 
Exp $
---------------------------------------------------------------------------------------------

It looks as though the system identifies the device, but no actual sound 
comes out of the speakers. (Sound continues to work fine in Windoze).

Any suggestions?