Description of problem:
Some time in the last fortnight or so, sound stopped working on my laptop (IBM
X30 (26724XG)

Version-Release number of selected component (if applicable):
alsa-lib-1.0.16-3.fc9.i386

How reproducible:
Always

Steps to Reproduce:
1. aplay -d hw:0 /usr/share/sounds/startup3.wav
(or paplay or play)
2.
3.
  
Actual results:
control passes to aplay for about the right length of time,
but no sound is heard.

Expected results:
An irritating jingle should come out of the loudspeaker.

Additional info:

This all worked up to some point in the last fortnight
(presumably an update).  I'm afraid I can't say more
accurately than that because I don't make much use of the
sound when I'm at home (but I do use it when on the train,
and I'm going to be soon). The terminal bell (pcspkr) works,
sound works in Windows XP.

I've tried running with the kernel (2.6.25-14) that comes in
the installation iso, but sound still doesn't work though it
did with that kernel in the original install, so I don't think
it's a kernel problem. There's no surround sound in
gnome-volume-control, so bug #449739 doesn't apply, I've
tried muting, changing level and unmuting the pcm in
alsamixer (and gnome-volume-control) as per bug #438448#c8
to no avail, so it's not that either. 

I've tried 0,1,2,3,4 as values for the ac97_quirk parameter
to snd_intel8x0, but that just seems to modify the click
made when the module is loaded.

pavucontrol under the playback tab says "No streams
available". I don't know if that's significant because I
didn't look at it when sound was working. Under output
devices it lists

ALSA PCM on front:0 (Intel 82801CA-ICH3) via DMA

and nothing else.

lspci -nn -s 00:1f.5
00:1f.5 Multimedia audio controller [0401]: Intel Corporation 82801CA/CAM AC'97
Audio Controller [8086:2485] (rev 02)

I'll attach output of
for i in $(hal-find-by-capability --capability alsa); do lshal -lu $i; done
>/tmp/hal-caps