[sane-devel] Canon Canoscan Lide50 broken in 1.0.21 ...

[Mali]

Hi,

as of 1.0.21 support for Lide 50 (genesys backend) seems to be broken.

Scanning in gray or lineart mode makes the head move a little bit (some 
millimeters), stay in that position and make a high-frequency noise for 
some time and then return to the starting position. As to my 
understanding the head is positioned at the starting position for the 
actual scan, the scan itself fails. The resulting image is completely black.

When scanning in color mode, the behaviour is different. The head 
actually moves during scanning. It looks like it is moving at twice the 
intended speed: When the whole page has been scanned, it can be seen in 
"Simple Scan" compressed to half the normal height. The head continues 
to move against a mechanical stop inside the scanner for the some time, 
producing the other half of the image in "Simple Scan" (and a noise even 
uglier than the one above).

I am quite sure that I have seen the gray/lineart behaviour in color 
mode, too, but at the moment cannot explain what triggers either of the 
failure modes.

I am trying this on a Ubuntu Maverik x86_64 system. Debian Squeeze 
(x86_64 and Armel) behave the same. Frontends used were Simple Scan and 
scanimage.

After going back from libsane 1.0.21-2ubuntu2 to 1.0.20-13ubuntu2, 
everything again works as normal. So, to me, it looks like something 
might have changed from 1.0.20 to 1.0.21 breaking the compatibility with 
the older scanners.

As far as I see, others are affected by the same problem:

https://bugs.launchpad.net/ubuntu/+source/sane-backends/+bug/680892

http://lists.alioth.debian.org/pipermail/sane-devel/2010-August/027343.html

Otherwise, I found no indication this behaviour has been discussed on 
this list.

Maybe, it already to late for 1.0.22, but hopefully the working state 
can be restored.

Kind regards,

Mali