connecting usb scanner to laptop

Roch Jaszynski rjaszynski at
Thu Jan 5 13:06:48 UTC 2006


I have exactly the same problem and would also be grateful if anyone
could explain how to solve it or go around.



manuel borowski:

> 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...
> Regards,
> Manuel 

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