Comment 109 for bug 1136110

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