[sane-devel] HP ScanJet 6300C head moving back/forth during scan >200dpi

[Michael Ole Olsen]

Hello, I am having problem using my HP ScanJet 6300C with libusb and
xsane+sane backend from debian testing. I have also tried debian etch
version on another computer with same issues, and I even tried
downgrading my sane backend (then it went completely insane and almost
broke the scanner). Right now im testing on a cometely fresh install of
Debian/testing.

There are no scanner modules loaded/in kernel and the kernel is PREEMPT 2.6.23.9

When I do a scan, it waits about 6-8 seconds before scanning (just like
it is calibrating), then it moves the scanner head back and forth while
scanning (only when i get over approx. 200dpi)

I did read somewhere on this mailinglist, that it had to do with USB
bandwidth, so the scanner must wait at above 200dpi for the transfer of
data to complete over USB.

I'm using it with a high-speed USB 2.0 hub, so i dont see how there
could be any kind of transfer-bottleneck.

I tried adding 'option enable-image-buffering' to top of
/etc/sane.d/hp.conf just like man sane-hp says to make it global, with
no results.

I tried enabling debugging a few times, the output didn't seem useable,
but I can post it if needed.

I have had the same issues with a plustek scanner (Canon LIDE 30) and libusb: grinding
noise and scanner head moving forth and back while scan > 200dpi.


Can anybody help me sort this out?


best regards
Michael Ole Olsen
gnu at gmx.net