[sane-devel] USB-sniff help with Canon FS2720U

Tabor Kelly tkelly-sane-devel at taborandtashell.net
Mon Jul 17 20:15:12 UTC 2006


I am hoping to write a SANE backend for my Canon FS2720U slide
scanner. After playing with Snoopy Pro and deciding that it was
lacking in many regards, I have switched so USB-sniff. However, I am
new to USB and device drivers in general and I am looking for some
help reading the USB-sniff output.

Specifically, I want to know how the elements of the USB-sniff output
map to the USB 1.1 specification. Here is the first log I attempted to
read (http://tabor.taborandtashell.net/sane-fs2720u/turned_on.LOG).
This is just what I get when I turn on the scanner for the first time.
So, I have a long list of questions and I have searched for answers
but I couldn't find any.

What does Status in USB-sniff map to in the USB 1.1 spec?

Does URB_FUNCTION_CONTROL_TRANSFER refer the the Control Transfer
discussed in the USB 1.1 spec? If so, what is a
URB_FUNCTION_CLASS_INTERFACE? I couldn't find it in the spec.

What are the TransferFlags and why can't I find their description in
the USB 1.1 spec?

TransferBuffer is just the memory address of the start of the buffer,

What is TransferMDL?

What is UrbLink?

Do RequestTypeReservedBits, Request, Value, and Index in USB-sniff map
to bmRequest, bRequest, wValue, and wLength respectively in the USB
1.1 spec?

Thank You,

Tabor Kelly

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