The desktop I am on right now is running Ubuntu 8.10, complete with all of its PulseAudio glory (frankly, I wish they had waited until that glory was a little greater before making it the de facto sound system) and I had a problem that ran as follows: I would boot up the machine and sound would work beautifully for a while. After a couple days or so, sound would inexplicably stop working. I fired up the sound preferences applet, hit the magic "Test" button and, lo and behold!, it failed with a message containing the words:
audioconvert ! audioresample ! gconfaudiosink: Failed to connect: Connection refused
So, I would kill, restart, or start any sound service or process I could find, but sound did not return. A system reboot (something I am loathe to do) solved the problem--for a couple of days, then I was right back at the beginning. I did some googling this time around and ran the command
$ pulseaudio -vv
To see the output. There was a great deal there, but the key was this:
Error opening PCM device hw:0: Device or resource busy
Okay. So I googled it. After reading a couple of almost relevant posts, I opened up /etc/defaults/pulseaudio and changed
PULSEAUDIO_SYSTEM_START=0
to
PULSEAUDIO_SYSTEM_START=1
then ran
$ sudo /etc/init.d/pulseaudio start
and sound came alive again! What is this doing? Basically, it takes PulseAudio out of userland and puts it at the system level. The comments indicate that this is a bad idea because shared memory wouldn't work and "could potentially allow users to disconnect or redirect each others audio streams". Both arguments seem rather academic. I am sure the lack of shared memory access could be a performance hit, but having no sound is the ultimate performance hit (it consumes 100% of the resources with a performance of 0%!) and my untrained ear could hear no difference. The second one is relevant if you have multiple users on the same box who are running sound. This, of course, is not true on my desktop where I am the only user. Again, I understand the desire to close a security vulnerability but, personally, I would rather have sound and chance someone listening to the Derek Webb song I am listening to than have to reboot my computer every couple of days.