On Sat, Jul 28, 2012 at 11:30 AM, Iain Mott <mott@reverberant.com> wrote:

Hi list - i have an installation that's been running for a week and has
suddenly failed.

Uses ubuntu 11.10 and a hdsp/multiface setup. What is happening is Jack
is failing to start

There is a "D-BUS: JACK server could not be started" error when QjackCtl

this is confusing and misleading and just incredibly dumb. but, moving on ....

Sat Jul 28 12:27:20 2012: JACK server starting in non-realtime mode

not too smart, but okay.

Sat Jul 28 12:27:20 2012: [1m [31mERROR: Failed to acquire device
name : Audio2 error : Input/output error [0m
Sat Jul 28 12:27:20 2012: [1m [31mERROR: Audio device hw:DSP cannot be
acquired, trying to open it anyway... [0m

ok, so device acquisition logic is just completely optional ... fine. moving on.

Sat Jul 28 12:27:20 2012: creating alsa driver ... hw:DSP|hw:DSP|4096|2|
96000|0|0|nomon|swmeter|-|32bit
Sat Jul 28 12:27:20 2012: configuring for 96000Hz, period = 4096 frames
(42.7 ms), buffer = 2 periods
Sat Jul 28 12:27:20 2012: ALSA: final selected sample format for
capture: 32bit integer little-endian
Sat Jul 28 12:27:20 2012: ALSA: use 2 periods for capture
Sat Jul 28 12:27:20 2012: [1m [31mERROR: ALSA: cannot set hardware
parameters for capture [0m

and there we have the "root" of your problem. first thing to try is to start varying the parameters and see if anything makes a different (period size being the obvious one, but also sample rate).