On Sun, Jun 30, 2013 at 7:42 AM, James Stone <jamesmstone(a)gmail.com> wrote: In trying to get support with this usb problem in kernel 3.8: Actually, re-reading his reply, I think he has worked most of it out, and the main problem was me not providing enough info.. But now it seems to have got down to how jack actually communicates with the usb driver.. Seems to me it must be a kernel-side problem because it works on 3.5 - but apparently the code for 3.5 was not doing it the "right way".. He writes: "The usbmon trace for 3.5 shows that the audio driver was really using the equivalent of 5.5 frames/period and 8 periods/buffer. This means the actual latency (as far as the kernel is concerned) was 5.5 / 44100 = 0.125 ms, as I mentioned earlier. The usbmon trace for 3.8 shows that the audio driver was really using the equivalent of 11 frames/period and 8 periods/buffer, for a latency of 11 / 44100 = 0.25 ms." James