Comment 36 for bug 53216

Ok, here is some hopefully more useful information, captured with

$ strace -t -p $(pidof skype) 2>| skype-write-log.txt

just before doing something that outputs sound in skype after it has been idle for a while. My system hung for 11 seconds, which is captured in this strace log (although I didn't strace the process from the beginning, so any initialisation is lost).

The "interesting" call just before the hang is futex(), which is used for locking in user space. Coincidence?