Alan, I've tried to build a kernel with CONFIG_USB_DEBUG. In the config editor I searched for the symbol CONFIG_USB_DEBUG and only one match was found. I set it, compiled and installed the kernel. This kernel is:
root@whitlam:/boot# uname -r 3.7.0-7-generic and from /boot/config-3.7.0-7-generic there is only one reference to that symbol, but it is in the HID section which seems odd. # USB HID Boot Protocol drivers # CONFIG_USB_KBD=m CONFIG_USB_MOUSE=m CONFIG_USB_ARCH_HAS_OHCI=y CONFIG_USB_ARCH_HAS_EHCI=y CONFIG_USB_ARCH_HAS_XHCI=y CONFIG_USB_SUPPORT=y CONFIG_USB_COMMON=y CONFIG_USB_ARCH_HAS_HCD=y CONFIG_USB=y CONFIG_USB_DEBUG=y CONFIG_USB_ANNOUNCE_NEW_DEVICES=y The periodic file (comment #86) has data in it for one of the two devices, I assume that's the DAC whic is playing right now. Q1. For this to help, do you need see exactly the same sound being played back (I don't know how to do this, but it must be easy to find a tone generator online)? Q2. How much data do you need? Here is some data I see. This is from the kernel above, which has no crackling. I'm hoping that you can confirm this is what you need. 0: qh2-0e01/efda8640 (f5 ep3in [1/3] q1 p32) 1: qh256-0001/f6f98dc0 (h2 ep1in [1/0] q1 p2) 2: qh2-0e01/efda8640 4: qh2-0e01/efda8640 6: qh2-0e01/efda8640 8: qh2-0e01/efda8640 10: qh2-0e01/efda8640 12: qh2-0e01/efda8640 14: qh2-0e01/efda8640 16: qh2-0e01/efda8640 18: qh2-0e01/efda8640 20: qh2-0e01/efda8640 22: qh2-0e01/efda8640 24: qh2-0e01/efda8640 26: qh2-0e01/efda8640 28: qh2-0e01/efda8640 30: qh2-0e01/efda8640 32: qh2-0e01/efda8640 34: qh2-0e01/efda8640 36: qh2-0e01/efda8640 38: qh2-0e01/efda8640 40: qh2-0e01/efda8640 42: qh2-0e01/efda8640 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1136110 Title: USB Audio Codec choppy playback To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1136110/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
