[LAU] usb soundcard: xruns and latency even with -rt kernel

[Karsten Wiese]

Am Freitag, 28. Dezember 2007 schrieb Jacob Lee:
> I'm using an M-Audio Transit usb soundcard with the kernel 2.6.22-rt,
> as packaged by ubuntu. I'm running jack right now with -p 3 -n 512,
> and I still get xruns, typically of values less than .03ms, every few
> minutes.

You can try increasing the client timeout, i.e:
	$ jackd -R -P60 -t200 ...
helps here using kernel 2.6.24-rcx.

((
 jackd calls poll() with a timeout value of a period's ms each time
 it triggers the external clients. Linux's poll() call can timeout at 
 (specified timeout - jiffy). IMHO either linux needs to be fixed to 
 implement posix poll() timeout handling, or jackd has to supply 
 (a period's ms + a jiffy's ms) as parameter for the poll() call.
))
      Karsten