[sane-devel] Re: CanoScan LiDE 30 usb scanner won't scan but passes -T tests

Christopher Marshall christopherlmarshall@yahoo.com
Mon, 29 Dec 2003 06:28:09 -0800 (PST)

--- Christopher Marshall <christopherlmarshall@yahoo.com> wrote:
> I am using sane front end 1.0.11 and backend 1.0.13 on slackware linux 9.0.
> I configured /etc/sane.d/sane.plustek.conf thusly:
>    [usb] 0x4a9 0x220e
>    device /dev/usb/scanner0
> When I ran scanimage -L, all of the tests passed.
> When I try to run scanimage > image.pnm, I can see the scanner being calibrated and the internal
> bar being moved but when it comes time to scan the image, I get a brief noise, the bar never
> moves
> past the initial set point, and the image written is all black.
> Any ideas?
> Chris Marshall

Well, I've got it working.  I think the key was one of these three things:

1) plugging the scanner's usb cable into a hub, and then plugging it into the host controller
2) using "insmod uhci" instead of "insmod usb-uhci" or vice versa.
3) running "scanimage -T" once before running "scanimage > image.pnm"

Oddly enough, my home computer and work computer differ on whether the scanner will work when
plugged in through a hub or not.  

The lesson for me is this: USB, while a great technology, is far from mature both in terms of the
hardware and linux drivers.  What should work in all combinations of host controller drivers, and
hub/host-controller interconnects, may only work in certain combinations.  So before throwing your
hands up, try out different variations *for each computer* you are trying to get it to work on.

I have to say I am pretty happy with the quality of the scans, although I am more interested in
scanning documents than pictures, so perhaps I am easy to please.

Chris Marshall

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