[sane-devel] Accessing scanner through libusb fails with "invalid argument"

[Dan McGhee]

Sebastian Reichelt wrote:

>Hello!
>
>I have a Tevion MD9458 scanner which I would like to get to work with
>Linux. Apparently it is supported by SANE, and sane-find-scanner detects
>it correctly. However, when I try to access it with xsane or scanimage,
>I get the message:
>
>open of device gt68xx:libusb:002:... failed: Invalid argument
>
>This happens when I am root or a normal user with appropriate
>permissions. The right number increases every time I try this, as
>somehow the file /proc/bus/usb/002/027 disappears and a new file
>/proc/bus/usb/002/028 appears, and so on.
>  
>
This happened to me before I learned that my kernel was loading 
hpusbscsi. There are apparently some problems with this 
module--documented in this list's archive. I recommend that you run 
`lsmod` to see if this module is loaded. If it is, here's what I did:

1. Turn off the scanner--I unplugged mine.
2. run `modprobe -r hpusbscsi
3. Turn on the scanner
4. `scanimage -L
5. `xscanimage` [backend-name]:libusb:AAA:BBB, where AAA:BBB would be 
002:027 or 002:028 from your info above.

If this works, rename hpusbscsi in your kernels driver directory and you 
might be "good to go."

If it's not hpusbscsi, I'm sorry that I don't have enough expertise to 
provide any other recommendations.

Good luck,

Dan