Comment 16 for bug 316430

That is a different bug. I guess it is some kind of race condition what gets started first, either pulseaudio or the canberra startup sound. If you don't have alsa configured to use pulseaudio, then canberra, if it gets started before pulse, probably detects that no pulseaudio is running and then uses alsa to play the sound, thereby locking the alsa device. If pulse gets started during that time it can't access the alsa device because of that.