On Sun, 25 Oct 2009 18:03:09 +0800 Ray Rashif <schivmeister@xxxxxxxxx> wrote: > 2009/10/25 <hollunder@xxxxxx> > > > On Sun, 25 Oct 2009 11:40:16 +0100 > > rosea grammostola <rosea.grammostola@xxxxxxxxx> wrote: > > > > > Hi, > > > > > > I found this info: > > > > > > > > > "USB and jack > > > > > > The USB interrupt period is 1 msec. To be able to get lower > > > latency with jack when using it with an USB device, you have to > > > use a setting as 48kHz and 3 period. It will makes the buffer > > > time a multiple of 1 msec and you will get a much lower latency > > > as with the default 2 period. Additionaly, loading the > > > snd-usb-audio with the parameter "nrpacks=1" will give you a much > > > lower latency (for this to work take care that > > > CONFIG_USB_BANDWIDTH is not set and CONFIG_USB_DYNAMIC_MINORS is > > > not set in your running kernel)." > > > > > > > > > > > http://proaudio.tuxfamily.org/wiki/index.php?title=Howto_RT_Kernel#USB_and_jack > > > > > > > > > 1) is this info still up-to-date? > > > 2) how do I exactly take care of this: > > > "Additionaly, loading the snd-usb-audio with the parameter > > > "nrpacks=1" will give you a much lower latency (for this to work > > > take care that CONFIG_USB_BANDWIDTH is not set and > > > CONFIG_USB_DYNAMIC_MINORS is not set in your running kernel)" > > > > > > (Debian (based) systems) > > > > > > \r > > > > In my experience 48kHz/3 periods works a bit more stable, the > > possible latency settings in jack don't really change, 64 frames is > > still the lower boundary and unstable. > > > > But I haven't heard about 2) and am very curious about this > > myself. > > > > Philipp > > > 2) Edit /etc/modprobe.conf or /etc/modprobe.d/modprobe.conf with: > > options snd-usb-audio nrpacks=1 > > And to "make sure". you have to have the kernel options changed. make > menuconfig, and press "/" to search for the two options. > > Philipp: we already dealt with that one but _without_ substantial > cause-and-effect http://bugs.archaudio.org/task/5 Thanks, you're right, CONFIG_USB_DYNAMIC_MINORS is not set and CONFIG_USB_BANDWIDTH doesn't even show up. I'll try to load with that option tomorrow and see how it goes. Philipp _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
