The sound on my Ubuntu box stopped working this morning.
I was getting a ton of messages “ALSA lib pcm_dmix.c:819:(snd_pcm_dmix_open) unable to open slave”. I bounced artsd, and it said that very message on startup. After the usual futzing around, such as looking in syslog and finding nothing, I straced it, and searching for dev files noticed:
open("/dev/snd/pcmC0D0p", O_RDWR|O_NONBLOCK) = -1 EBUSY (Device or resource busy)
Well, that certainly looks like a culprit, would have been nice if artsd could have actually reported that as an error.
Now, let’s fuser /dev/snd/pcmC0D0p — huh, the two xpdf ’s I’m running have it open. (WTF is xpdf permanently grabbing my pcm device?) Kill the xpdf ’s, now artsd can start cleanly, and I have working sound again.
I have no idea how normal users (Ubuntu’s alleged target market) are supposed to handle this. Reboot, most likely. Works for Microsoft.