[linux-audio-user] xruns every 30 seconds

[Dominic Sacré]

Hi,

I'd like to run jack on a rather old laptop (IBM Thinkpad X21, P3 700MHz).
The problem is that I'm getting xruns almost every 30 seconds. That is,
not every time, but the interval between two xruns is always an exact 
multiple of 30 seconds.

There's quite a long dropout of almost one second each time an xrun 
occurs.

Jack output looks like this:

delay of 34010.000 usecs exceeds estimated spare time of 4075.000; 
restart ...
03:32:01.992 XRUN callback (13).
delay of 31715.000 usecs exceeds estimated spare time of 4124.000; 
restart ...
03:32:32.003 XRUN callback (14).
delay of 39019.000 usecs exceeds estimated spare time of 4086.000; 
restart ...
03:33:01.993 XRUN callback (15).
delay of 41527.000 usecs exceeds estimated spare time of 4078.000; 
restart ...
03:34:02.000 XRUN callback (16).
delay of 33218.000 usecs exceeds estimated spare time of 4124.000; 
restart ...
03:34:32.010 XRUN callback (17).

I'm running Ubuntu Dapper with vanilla kernel 2.6.17.11. This is with a 
USB audio interface (Behringer UCA 202), and jack is running realtime, set 
to 48kHz, 3 periods, 128 frames, duplex (tried playback only, too).

Any ideas what might be causing these xruns?

Thanks,
    Dominic