[sane-devel] USB2 4 port hub and write_scanner(0): funky result: -32

Julien BLACHE jb@jblache.org
Wed, 20 Apr 2005 17:54:46 +0200

Alexander Kempshall <member@aikempshall.freeserve.co.uk> wrote:

> I've recently bought the Trust 420A 4 Port Compact USB2 Hub. On the
> http://www.qbik.ch/usb/devices/ there is a suggestion that it is Linux
> compatible.

A USB hub needs no OS driver, it just works (tm).

> In Slackware 10.1 when the hub is connected to my Canon N670U scanner,
> start Kooka, the scanner is recognised but when I try to scan nothing
> happens. Close Kooka down and start again the scanner is no longer
> recognised. Unplug the USB cable the machine crashes. In dmesg I get
> the following
> scanner.c: write_scanner(0): funky result: -32. Consult
> Documentataion/usb/scanner.txt.

Don't use the scanner module, it's obsolete, unmaintained, etc. rmmod
it, and either remove the scanner.o file or add it to the hotplug
blacklist (if you have hotplug installed).

> The Scanner works perfectly if plugged directly into a usb port on the
> mother board. Also the scanned works perfectly plugged into the
> external hub using knoppix.

Does your USB hub come with an AC adapter ? If yes, is it plugged in ?
Same question for your scanner.

If neither your USB hub nor your scanner come with an AC adapter, then
you'll need to get another, AC powered, hub so that the scanner will
get enough power from the USB bus.

Currently, your scanner is under-powered, as you have too many
bus-powered devices plugged on your USB bus. Hence the transfer


Julien BLACHE                                   <http://www.jblache.org> 
<jb@jblache.org>                                  GPG KeyID 0xF5D65169