[sane-devel] Canon LiDE30 errors when calibration isn't cached

[Rich J]

Hi,

After trying and failing to get my Canon LiDE30 USB working on Gentoo
2.4.24 and 2.6.4 on a PC w/uhci and a laptop w/ohci, I finally got it to
sort of work on the laptop running Gentoo 2.6.8, sane-backends 1.0.14-r4,
and libusb 0.1.8.

"scanimage -L" works great on each of the above kernels I tried, but all
attempts to scan or preview an image cause the scanner bar to move to
origin, then flash for 20-30 seconds and report "sane_read: Error during
device I/O" and abort.  I somehow managed to create a
~/.sane/Canon-N1240U_LiDE30.cal file while testing (no idea how!), and now
it works great.

If I remove the file, it doesn't matter what "option cacheCalData" is set
to -- it always fails.  Move the file back and all's well.

So, how does the cache file get created?  I'm assuming at some point when
"option cacheCalData" is set to 1, but if I try it now, no file gets
created and I get the error above.

Anyone who's got a successful run at this care to share their setup? 
Thoughts?

TIA,
Rich

p.s.  If anyone needs lengthy debug output or full files, let me know and
I'll post them.