USB packet sniffer

1. command / on device board
Make sure build with "CONFIG_DEBUG_FS" ( which generates /sys/kernel/debug ) "CONFIG_USB_MON" and "CONFIG_USB_DEBUG" (which generates /sys/kernel/debug/usbmon)
1.a

mount -t debugfs none_debugs /sys/kernel/debug

modprobe usbmon / insmod usbmon

1.b

cat /sys/kernel/debug/usbmon/1u

1u ==> by the bus number

2. With wireshark on PC

3. With USB sniffer tool

4. Test unit ready

sdparm --command=ready /dev/sda1