Yup, sure. It never returns. It's also definitely blocked waiting for the timer to tell it to "go".

I'm just going to have a go running Raspbian

Both command line. I was running as root and /dev/snd/timer is chmod 660 and belongs to root:audio so it's not a permissions problem.

I've put the question on the alsa-users mailing list with a link over to this. Let's see if we get anything...

Thanks. And "huh" the "interesting" one not the "duhh" one. It gets stuck polling a file descriptor. Edited highlights: open("/dev/snd/timer", O_RDONLY|O_NONBLOCK|O_CLOEXEC) = 3 fcntl64(3, F_SETFD, FD_CLOEXEC) = 0 ioctl(3, SNDRV_TIMER_IOCTL_PVERSION, 0xbedd62c8) = 0 ioctl(3, SNDCTL_TMR_START or SNDR...

As per subject I'm trying to get dmix running on alsa on a rev 2 model B - Arch (obviously) and sync'd to latest. Long story short: this aplay sample.wav works fine but this: aplay -D "plug:dmix" sample.wav does nothing. It starts up just fine then sticks at Playing WAVE 'sample.wav' : Signed 16 bit...