Hi Eliot,

Thanks so much for your response:

...

I am trying to work on dummy.c:

http://lxr.linux.no/#linux+v2.6.32/sound/drivers/dummy.c

as an exercise, and I'd like to modify it so it behaves as an 'oscillator'; [snip]

You are better to look at the loopback driver in alsa-driver repo:

http://git.alsa-project.org/?p=alsa-driver.git;a=blob_plain;f=drivers/aloop-...

You would put your generation code in clear_capture_buf()

Fantastic info - that is exactly what I needed :)

(Don't know why your response hasn't shown in the alsa-devel archives yet, hopefully my reply will bump it up there)

Cheers!