[sane-devel] Canon DR-9050C

m. allan noah kitno455 at gmail.com
Fri Aug 17 01:05:30 UTC 2012

Thanks for the traces, Philip. I have had sporadic reports of attempts
to use this scanner, but no-one has provided such detailed info.

Basically, the Canon DR series machines are scsi over usb. We add a 12
byte header to a normal scsi command. So, you can download the scsi
spec from many places online, and see how the basics work. Now, they
have added their own commands, and use various extensions to standard
command payloads, so we are forced to guess sometimes.

Wireshark makes things a little more difficult, because it shows all
the low level USB stuff, that really does not matter to us. So, you
have to learn to ignore every other packet in those logs, and the
first 0x40 bytes of the packets you do care about.

I took a brief spin thru your logs, and it appears that the scanner is
unhappy when we send the 0xd6 command, which I call SET_SCAN_MODE.
Your 'success' logs show instead the use of an 0xe5 command, whose
format is unknown to me. ISTR some other user reported this recently
for some other model.

So, the immediate course of action is to disable calls to ssm in the
sane backend, and see if it will scan. Then we make a series of small
area, low resolution scans in the working driver, changing one
parameter each time. Then we see how the calls to the 0xe5 command
change. It might be that we never determine what they do, or that they
only do something under the windows driver.

Then, we can use that info to update the backend to enable those
features, if they seem useful. Probably the best place to start is
some scripts to help you 'diff' pcap files.


On Thu, Aug 16, 2012 at 2:03 PM, Philip Gwyn <philipgwyn at gmail.com> wrote:
> This is annoying: To get the most recent wireshark working, I moved the dev
> to a machine with CentOS 6.  But it only has USB 1.0 and only works in
> 32bits.  However, it doesn't exhibit the problems I'm having with Canon's
> binary blob, specifically not waking up from stand-by mode.
> Pcap output of a sucessful canondr scan and unsuccessful canon_dr scan:
>    http://pied.nu/Sane/canon_dr-20120815-1130.tar.gz
> -Philip
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