[linux-audio-user] via82xx and jackd

Jesse Chappell jesse at essej.net
Wed Jan 21 13:17:27 EST 2004

Keith Parkins wrote on Wed, 21-Jan-2004:

 > Hi,
 > 1) I'm using alsa 1.0.1 with the latest version of jackd on a via kt400
 > mobo (VT8377) and a VT8233 audio controller. I have the low-latency/premp
 > kernel patches as well as the capabilities patch applied to a 2.4.22
 > kernel. I get xruns like crazy that average around 0.09 msecs when running
 > jackd in duplex mode. These disapear when running in either capture or
 > playback mode. I had seen that there may be some issues with the via82xx
 > chipset and jackd on the alsa list, but no solutions or description of
 > what the actual problems were. Am I stuck in a duplex-free zone or is
 > there a way to work around this? Will this affect my ability to use ardour
 > as multitracking device using the mic/line-in, or will it only cripple my
 > ability to use other programs as jack slaves?

What sample rate are you using?  Try the other one, (48000 or 44100)
and see if it's any better.

 > 2) Even with the capabilities patch, I get the following error when
 > running jack as a normal user:
 > JACK: unable to mlock() port buffers: Operation not permitted
 > cannot set thread to real-time priority (FIFO/20) (1: Operation not
 > permitted)
 > cannot use real-time scheduling (FIFO/10) (1: Operation not permitted)

You need to run jackstart, instead of jackd to make use of the
capabilities patch.  If you haven't been realtime, that might
explain your full-duplex overruns too.



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