[Jack-Devel] xruns on NVidia HMDI output

Greetings!

I am trying to get a very basic setup working. I would like to use jack 
in output-only mode. I only want to use a MIDI keyboard with a MIDI 
sequencer and something like zynaddsubfx. I don't care too much about 
audio latency. Simple, right?

Here is my set up:

Ubuntu 11.04 SMP 2.6.38-11-generic x86_64
jackd2 1.9.6~dfsg.1-5ubuntu1
10de:0be3 nVidia Corporation High Definition Audio Controller

This output device drives the audio on the HDMI cable. It only has 
SP/DIF outputs.

I am using pasuspender to finesse pulseaudio issues. I have jackd2 
running with real-time scheduling and locking memory. The machine has no 
other load. Two periods gives me tons of xruns. If I use 3 periods 
(helpful for snd-hda-intel?) then I don't get any xruns until I try to 
start a jack client. Any jack client (e.g. jack_metro) will cause lots 
of xruns. My HD TV outputs jack audio and it doesn't sound too bad, but 
I bet it would sound better if I could eliminate the xruns.

What more information can I provide? Is there some trick to getting this 
to work?

Thanks!

-- 
Joshua N. Pritikin
Department of Psychology
University of Virginia
Gilmer Hall 102; Charlottesville, VA 22903
http://people.virginia.edu/~jnp3bc

1316730683.14599_0.ltw:2,a <20110922223106.GQ3551 at pobox dot com>