ALSA: no sound, no error!

["[KS]" <lists04@fastmail.fm>]

Hi,

My system is an unstable Debian box and was running sound (with ALSA)
under KDE(and sometimes GNOME) without any problem till a few weeks ago.
But now I get no sound what soever. There is no sound if I do $cat
/dev/urandom > /dev/dsp   Also, when I try to play audio (audio CD or
mp3s) with XMMS everything seems to be running fine but there is no
sound! XMMS, xine, or other multimedia applications do not complain
about anything regarding sound system.

Could someone help or give tips on how to go about debugging the sound
problem?

Below are some details about the system:
arts is set to release the sound device after 2 seconds, and it looks
that its working. Testing sound from the Control Center>Sound and
Multimedia doesn't give any error either.

~$ lspci | grep Multimedia
0000:00:1f.5 Multimedia audio controller: Intel Corp. 82801DB/DBL/DBM
(ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 01)

~$ lsmod | grep snd
snd_intel8x0           33216  0
snd_ac97_codec         78360  1 snd_intel8x0
snd_pcm_oss            53344  0
snd_mixer_oss          19872  1 snd_pcm_oss
snd_pcm                92712  3 snd_intel8x0,snd_ac97_codec,snd_pcm_oss
snd_timer              24644  1 snd_pcm
snd                    55300  6
snd_intel8x0,snd_ac97_codec,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_timer
soundcore               9664  1 snd
snd_page_alloc         10020  2 snd_intel8x0,snd_pcm

~$ cat /proc/asound/cards
0 [I82801DBICH4   ]: ICH4 - Intel 82801DB-ICH4
                     Intel 82801DB-ICH4 with AD1981A at 0xfebff800, irq 201