[sane-devel] backend in progress: canon i-sensys mf4570dn, 'mfnp' protocol

[chrysn]

On Fri, Feb 25, 2011 at 10:45:35PM +0100, Louis Lagendijk wrote:
> Is there a backend that supports your device? If so, I could have a look
> at some packet traces to see if support for your devices IP-protocol is
> doable.

there is no backend that autodetects the device when on usb or ethernet,
none that is supposed to support it according to its description, and
the characteristic sequence of the protocol ('MFNP') i recorded from the
windows drivers is not found in the backend sources.

> I developed the code using an MP970 that died. I am now using an MP980.
> But the code works on a lot of devices using an ethernet or even
> wireless connection. Again, does the device work over USB?

it does have usb, and is supposed to scan over usb as well, but i didn't
dig too deep there because i'd use in on ip in practice. also, sniffing
usb is a bit trickier than sniffing ethernet, and i'd need another
virtual machine environment to do it.

> Not that I know of. Does python allow for an easy wrapping of
> C-libraries?

basically it does, and i've seen it has been attempted once, but there
is no further information than [1]. i've seen there is a network
backend as well; implementing that interface would probably be easier
and more portable.

[1] http://mail.python.org/pipermail/python-list/2006-March/977748.html

On Fri, Feb 25, 2011 at 10:53:36PM +0100, Louis Lagendijk wrote:
> I forgot to ask: could you send me a packet trace from a Windows scan so
> we can see if the protocol is similar to one of the already supported
> devices? The main problems is probably not the network protocol that the
> bjnp stuff does, but the actual scanner USB protocol. It would be best
> if you could put the trace somewhere on the web, so Nicolas could have a
> look at it as well as he is the maintainer of the pixma backend. I will
> have a look at the ip-stuff to see if that could easily be accomodated

i've atta^Wuploaded wireshark dumps from roughly the same scan using
windows and my program to [2] and [3]. as for usb, i didn't quite get
the vm for the windows driver working -- will continue to try, as i need
it for another project too anyway.

[2] http://downloads.amsuess.com/~camsuess/windows_scan.pcap.bz2
[3] http://downloads.amsuess.com/~camsuess/linux_scan.pcap.bz2

status update: the current state of the program is that i produce better
error messages than the windows driver, can scan even at higher
resolutions *g*, but at times (especially when experimenting with
options not seen in the windows driver) the device gets stuck to the
extent of needing a reboot; still investigating on this.

regards
chrysn

-- 
To use raw power is to make yourself infinitely vulnerable to greater powers.
  -- Bene Gesserit axiom
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