Comment 11 for bug 400682

Hmmm, still no sound. pkill pulseaudio wasn't good enough cause pulseaudio kept restarting. I saw this in .xsession-errors:
** (gnome-volume-control-applet:5093): WARNING **: Connection failed, reconnecting...

** (gnome-volume-control-applet:5093): WARNING **: Unable to get default source

I did have a volume control applet open and then one in the notification area. I removed the applet, then fiddled with the notification area one. Eventually it went away and I got this in .xsession-errors:
** (gnome-volume-control:18676): WARNING **: Unable to find stream for bar
Assertion 'pa_atomic_load(&(c)->_ref) >= 1' failed at pulse/ext-stream-restore.c:202, function pa_ext_stream_restore_write(). Aborting.

At this point I could kill pulseaudio and it wouldn't restart. So I did:
$ speaker-test -c2 -Dplug:front

speaker-test 1.0.20

Playback device is plug:front
Stream parameters are 48000Hz, S16_LE, 2 channels
Using 16 octaves of pink noise
Playback open error: -16,Device or resource busy
Playback open error: -16,Device or resource busy
Playback open error: -16,Device or resource busy
Playback open error: -16,Device or resource busy
Playback open error: -16,Device or resource busy
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 64 to 16384
Period size range from 32 to 8192
Using max buffer size 16384
Periods = 4
was set period_size = 4096
was set buffer_size = 16384
 0 - Front Left
 1 - Front Right
Time per period = 5.632618
 0 - Front Left
 1 - Front Right
...

After this, I noticed that pulseaudio had restarted itself. I checked /var/log/user.log and see:
Jul 18 15:56:23 severus pulseaudio[18671]: alsa-source.c: ALSA woke us up to read new data from the device, but there was actually nothing to read!
Jul 18 15:56:23 severus pulseaudio[18671]: alsa-source.c: Most likely this is a bug in the ALSA driver 'snd_hda_intel'. Please report this issue to the ALSA developers.
Jul 18 15:56:23 severus pulseaudio[18671]: alsa-source.c: We were woken up with POLLIN set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail.

So this seems it is likely it, but I don't know how to proceed. Please advise. Thanks!