scanner and usb-2 usb-3 connections

[François Patte <francois.patte@mi.parisdescartes.fr>]

Bonjour,

1-
I have usb2 and usb3 ports on my computer. When I plug my usb2 scanner
in an usb3 port, xsane cannot start.

Is it correct? My (usb2) mouse and keyboard work perfectly when plugged
in an usb3 port.

2-
If I start xsane from a terminal, I get this message:

Failed cupsGetDevices

What does it mean and how to correct this?

3-
xsane find the scanner (of course) but it also find the webcan!!! Is
there a way to avoid this?

Thank you.

-- 
François Patte
UFR de mathématiques et informatique
Laboratoire CNRS MAP5, UMR 8145
Université Paris Descartes
45, rue des Saints Pères
F-75270 Paris Cedex 06
Tél. +33 (0)1 8394 5849
http://www.math-info.univ-paris5.fr/~patte