Okay, I guess I've read enough marginally related threads, with no joy, to start my own on this problem.
When I plug my fi-4220c directly into the USB jack on the front panel of my computer, xSANE has no trouble seeing it. But when I plug it into a USB hub -- which works for every other USB peripheral I've ever plugged into it -- xSANE reports No Devices Found. But if I immediately run lsusb, there it is:
Granted, I can work around this by running a USB cable across my lap, but I'd prefer a more elegant solution, if there is one.druid@Jove:~$ lsusb
Bus 001 Device 010: ID 04c5:1042 Fujitsu, Ltd fi-4220c Scanner
Bus 001 Device 002: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 002: ID 0d8c:0201 C-Media Electronics, Inc. CM6501
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
I'm running 9.04-amd64.