[linux-audio-user] Intermitent Xruns...

Russell Hanaghan hanaghan at starband.net
Fri Apr 9 02:35:50 EDT 2004


I setup Qjackctl with jack and have had it running fine under normal
conditions on MDK 9.2 with the multimedia 2.4 kernel...I upgraded this
system with MDK 10.0 today but am using the 2.4 kernel still.

I use a Dell 650mhz / 256Ram laptop with LADSPA plugins ad a live FX box
on my PA> Usually use AMS with Freeverb and a delay with midi control to
switch FX on and off.

I have set this laptop up in a CII docking station now that houses 2
SBLive PCI cards. I have them chained with a modified .asoundrc file
that gives me 4 ins and 4 outs. I have been using Ardour as the host to
test this setup. I am running 3 mono channels with a Chorus, Gverb and
TAP Delay in eac respectively. Qjackctl, TOP and Ardour all report about
24% CPU load when all are active. I run acoustic guitar thru the Chorus
channel separately routed to a channel on my mixer and I run the other 2
channels in Ardour back in stereo fed from an Aux send on the mixer for
General Fx buss.

The above setup works fine when I fire it up. I run the multi card set
up (actually ttable from the Alsa website) at 512 2 RT (As root) The
system stay stable with no Xruns for about 5 minutes then the sound will
begin to distort. It will do that for a minute or so then Qjackctl shows
an Xrun or 2 and it clears. Sometimes Jack will shutdown but not always.
I try to shut down as many daemons and services as possible. The 2
SBlive's are on IRQ 10 (Host bridge to docking station I think) but
nothing else on that interrupt. I have tmpfs setup. It seems like
something is kicking in intermittently causing this but I see no spikes
in Gnome Resource monitor nor anything odd watching it in TOP when the
problem starts. Even though I upgraded the system, it did this
previously as I have tested this once before on the same setup with MDK

Any ideas? This seems so close to being useful but the unreliable
tendency is a show stopper for my needs.


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