Same problem here with Intel D54250WYK NUC box + Audiolab M-DAC which uses async USB connection for 24/96 audio.
It seems that the problem only occurs with Intel USB3 controllers. Unfortunately the internal USB2.0 headers in my NUC are controlled by the same USB3.0 controller, and there is no option in the BIOS to disable the XHCI (USB3) mode. I have indicated the problem towards Intel: https://communities.intel.com/message/255474#255474 Here is a discussion regarding the Linux xhci_hcd isochronous problem: http://www.spinics.net/lists/linux-usb/msg107264.html Last mail on 8 May 2014: "This does seem to point to an incompatibility between the driver and the Intel xHCI hardware. Figuring out what that incompability is may not be easy, though..." -- You received this bug notification because you are a member of Ubuntu Studio Bugs, which is subscribed to Ubuntu Studio. Matching subscriptions: UbuntuStudio Bugs https://bugs.launchpad.net/bugs/1308628 Title: xhci-hda does not support isochronous streaming on usb 2.0 devices Status in Ubuntu Studio: New Status in “linux-lowlatency” package in Ubuntu: Confirmed Bug description: I have a Presonus AudioBox 1818VSL (usb audio interface,) which was working flawlessly for about 2 years on ubuntu 12.04. I bought a new computer with usb 3 ports and installed 14.04, and suddenly the audio is popping and crackling. The computer is loading the 1818vsl as a usb 3 device using xchi-hda even though it's a usb 2 device and should use ehci-hda. From what I understand on this thread, this is a problem that affects other usb audio interfaces as well: https://forums.presonus.com/posts/list/33427.page I found other users in the forums having this problem. Since xchi-hda is prebaked into the kernel, the only workarounds are 1. Disable usb 3 in BIOS or 2. If you don't have that option in BIOS, compile a new kernel with xchi-hda and ehci-hda enabled as modules and then blacklist xhci-hda. These shouldn't be the only options for Ubuntu users! My proposal is build xhci-hda as a module in the default Ubuntu kernel so that the affected users can blacklist it without having to compile an entirely new kernel. There are very few usb 3 devices at the moment anyways, and this should have very little effect on performance for other users. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntustudio/+bug/1308628/+subscriptions -- Mailing list: https://launchpad.net/~ubuntustudio-bugs Post to : ubuntustudio-bugs@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntustudio-bugs More help : https://help.launchpad.net/ListHelp
