Tue Feb 17 10:08:52 CET 2009

linux usbmon

To enable usbmon in the 2.6.x kernel, follow these
steps :-

1) Compile the USB_MON module (Device Drivers / USB Support / USB
   Monitor) or compile it into the kernel

2) Enable debugfs in the kernel, rebuild the kernel
   and reboot using the new kernel

3) mount -t debugfs none_debugs /sys/kernel/debug

4) modprobe usbmon

5) Find the Bus to which the USB device connects (cat
   /proc/bus/usb/devices and look for the 'T:' line which gives the
   bus number

6) cat /sys/kernel/debug/usbmon/<Bus Number>t > /tmp/Bus<Bus
   Number>.txt (NOTE : It's <Bus Number>t, not just <Bus Number>)

7) Use the USB device

8) Kill the 'cat' command

9) Examine the file /tmp/Bus<Bus Number>.txt

Read /usr/src/linux/Documentation/usb/usbmon.txt to
decode the output :-)