[sane-devel] Scanner failure when connected via USB3

[Mike Cloaked]

On Tue, Oct 28, 2014 at 1:21 PM, m. allan noah <kitno455 at gmail.com> wrote:

> I was able to somewhat parse the logs using a bit of perl. I am
> suprised about the difference in file size. Where you making the scans
> with the same parameters in both cases?
>
> allan
>
>
>
OK - I have been working on this with a bit of free time today.   First to
answer your question the vuescan scan of the sample document completed
without error whereas the scan with xsane failed to complete and hung
before it did very much which may explain the difference in the file sizes.

Secondly i set up wireshark this afternoon, and got it all running to
capture usb data on the bus that the scanner is connected to.  Having
completed a capture for a vuescan run scanning the same docuument as
previously. I then reset the scanner, and wireshark, and ran a scan in
xsane - but instead of hanging it worked!  The only change since the
previous time I booted the same laptop is that I ran a system update - but
there was no obvious package that was updated that would have contributed
to the changed behaviour!

So I have the usb packet capture files for vuescan doing a single complete
scan, a 2nd capture for xsane doing a pre-scan, and two runs where a full
scan of the document at 300 dpi was made successfully with xsane with the
scan window left untouched from the pre-scan, as well as one with the scan
window set to the reduced image for the small document on the platten.

However this is the first time that the scanner has ever worked to complete
a scan with xsane.  I have looked through the package dependency tree to
see which package may be a dependent one for xsane that was updated after
booting the machine today. The only one was mesa and maybe mesa-dri but I
would have been surprised if that update affected the scanner operation
from within arch linux. I was also beginning to suspect the libusb package
until today but that was not one of the packages that was updated.

So right now I am perplexed, but I will boot the machine again in the next
day or so, and run exactly the same test to see if it still works as it did
today, and will report back on the outcome.  It would be nice to know if
indeed one the the package updates did result in the change or if this it
is that the scanner will most of the time still fail to work.

I have the packet capture files as well as the packet-dissection text as a
set of files, and after setting up the test again next time if the scan
fails as usual I will capture the data for that as well.

Mike

-- 
mike c
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