[sane-devel] debugging/tracing usb commands?!

[Daniel Franke]

Hi all,

I'm currently trying to access my HP Scanjet 4570c. I already got a basic 
framework - courteys of Bertrik - but now I'd like to see the actual bytes I 
send to the device. Any attempt to talk to the scanner fails with "broken 
pipe" (translation: "babble detected"). 
I enabled "USB verbose debug messages" (CONFIG_USB_DEBUG) as a first shot, but 
this doesn't seem to report any bytes sent down to the kernel by libusb's 
ioctl() calls. I'd like to see the bytes in a similar fashion as snoopypro 
captures them - any hints, tools, kernel options? If posssible, I'd prefer to 
use standard tools/options before attempting to patch the kernel (or libusb) 
to print debug messages on my own.

Thanks in advance

	Daniel