connecting usb scanner to laptop

manuel borowski manuel.borowski at
Wed Jan 4 09:48:58 UTC 2006

I want to connect my scanner to laptop and use the sane library to
actually scan an image.  However, there seems to be a problem, i.e.
scanimage and xsane are not able to startup and give this error code :
scanimage: open of device gt68xx:libusb:004:012 failed: Invalid argument

At the same time, following log message appears :
Jan  4 10:36:41 localhost kernel: [4299192.689000] usb 4-2: USB
disconnect, address 12
Jan  4 10:36:41 localhost kernel: [4299192.884000] usb 4-2: new full
speed USB device using uhci_hcd and address 13

I know that the scanner (MD9459) has no onboard firmware and that a
small firware file needs to be downloaded before the scanner actually is
able to work.  So, my guess, from the traces, is that scanimage
(xsane) :
-find out the usb bus/device of the scanner (4/12 in the example above)
-download the firware file
-disconnect the usb to kick start the firware in the scanner
-try to connect to the scanner again, on the same bus/device (4/12)

However, after disconnecting the scanner (3rd point above), the scanner
driver (uhci_hcd?) enumerates all usb devices again, and for some
reason, it gives the scanner a new device number (13).  This is not
known to scanimage, which still tries to access the scanner via the
previous device number...  and fails :-(
I can imagine that incrementing the device number is something from the
usb spec, so the problem lies more on the sane level...
Anyway, any suggestions?

I'm using the latest sane, xsane, libusb drivers (did an update this
morning), but the problem persists...


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