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

stef stef.dev at free.fr
Mon Jan 3 21:08:10 UTC 2011

Le Monday 03 January 2011 13:57:35 Mali, vous avez écrit :
> 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
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	thanks for the bug report. Since you can run a working and a non working 
version, it would be higly interesting to run scanimage with debug enabled 
with bot versions so that I can try to compare bog debug traces and find what 
is going on.
	You'll enable debug log by doing in a command shell:
then by running scanimage in the same command shell:
scanimage -d genesys  >scan.pnm 2>debug.log
	You'll need the debug version of the packages. Send both debug.log files.

	Last you may try a recent package at https://launchpad.net/~stef-
dev/+archive/sane-backend-genesys so you'll can check if the bug is still 
present in the git tree.


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