"Mark Haney" <mhaney@...> posted
47FDFD4E.1050301@..., excerpted below, on  Thu, 10 Apr 2008
07:43:10 -0400:

> I've beat my head on this for a week now and I can't come up with any
> answers.  For some reason sound has stopped working completely on my
> laptop.  I've checked dmesg and syslog for any errors and nothing shows
> up concerning the kernel having problems loading the driver (ATI IXP).
> I've not updated the kernel until yesterday (was using 2.6.23-r9 for a
> month prior to this morning when I booted up into the new .24 kernel
> (-r4) and still no sound.  It seems rather obvious that it's a
> library/software problem, but I have no idea how to start looking for
> that.  I've run revdep-rebuild a couple of times and it's rebuilt
> non-sound related packages.  alsamixer has the sound ard right and the
> volume level right.

OK, simple stuff first.

If you hadn't changed the kernel or alsa about the time it happened... 
you mentioned the sound card was still right and the volume was up, but 
didn't mention whether you checked the mute.

Also, check any switches.  On some cards, switching the digital sound on 
switches analog sound off and the reverse.  There may also be a toggle 
switch for the on-card amplifier.

You don't mention your setup.  Here for instance the computer output is 
to a regular home audio system channel input.  If your system is similar, 
check that the system in question still plays the radio or other input, 
IOW, that it's the computer that's out not the home audio system, and 
check the cabling between the two.  If you run directly off the card to 
speakers, make sure they're plugged in, and if powered, that they have 
power and are on.

Try using alsamixer from a terminal window or the console command line as 
your mixer.  I've noted that sometimes the regular GUI mixers get mixed 
up and don't show the critical controls.  In particular, I had a card at 
one point that had a mute or toggle of some sort that about half of the 
GUI mixers couldn't see or control, but alsamixer could.  It had to be in 
the right position to play, so for awhile, at every boot, I had to load 
alsamixer and toggle that switch, before I got sound.  After that, I 
could use whatever GUI mixer I wanted to control volumes and the like, 
but I had to use alsamixer to turn it on properly at every boot.  While 
that issue is long since resolved, since then, every time I have a 
problem, I use alsamixer to see what's really going on.

Finally, while testing, use a player that has a visual output as well.  
That way, you can /see/ if it's actually playing, too.  I've had a couple 
times with sound servers and/or Internet audio streams where it was 
supposed to be playing according to the input graph (the incoming 
Internet stream or player into the sound server), but the output graphic 
was flatlined, indicating there was no actual sound being played (due to 
a buffering error, either with the Internet stream or with the sound 
server).  In both cases, I thought it was alsa or the amplifier until I 
noticed the flatlined activity monitor indicating nothing actually 
playing.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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