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

Mali mali8217 at nurfuerspam.de
Tue Jan 4 22:43:11 UTC 2011

Hi Stef,

ahh, thanks for the reply. 1.0.22 from your PPA seems to work! In case 
they are of interest, I have attached the debug logs for all three 
versions I tested.

I have no idea, whether this is significant, but one difference I saw 
was a line concerning the invocation of "gl841_init_motor_regs_scan":

[genesys_gl841] gl841_init_motor_regs_scan : scan_exposure_time=5600, 
scan_yres=300, scan_step_type=1, scan_lines=3531, scan_dummy=0, 
feed_steps=373, scan_power_mode=0, flags=0

For 1.0.20 and 1.0.22, flags is set to 0, whereas it is set to 2 in 1.0.21.

Ok, so lets see, if can get it work again on that armel system.

Kind regards,


Am 03.01.2011 22:08, schrieb stef:
> 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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>>               to sane-devel-request at lists.alioth.debian.org
> 	Hello,
> 	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:
>   export SANE_DEBUG_GENESYS=255
> export SANE_DEBUG_GENESYS_GL841=255
> 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.
> Regards,
> 	Stef

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