[sane-devel] Canoscan 8400f

[m. allan noah]

On Fri, Oct 2, 2009 at 11:53 AM,  <brian at amason.net> wrote:
> I'm back at considering working on a driver for the Canoscan 8400f. I have
> been requested by another developer to help do this. I have the Mac
> driver. Mac, if I remember it is *nix based now. What is the take on
> driver writing in regards to RE drivers to implement drivers? Has anyone
> ever decompiled OSX drivers? What would be a recommended decompiler? I do
> not have any MAcs so could never install the driver and run it,

IMHO, decompiling has never been worth it. You spend more time trying
to figure out their code than figuring out the communication protocol,
which is what you really need.

> but the
> Canoscan 8400f is a fairly complex and high end scanner.

It costs ~$150 new? it is neither complex nor high end. It is cheap
consumer-grade junk, which appears to use a third-party chip from
genesys logic. This is a good thing, because we already have a working
backend for the older GL chips, and the newer ones are somewhat
compatible.

> I'd like to make
> a Linux driver that supports 100% of the features. Is it a taboo to
> decompile drivers for making Linux drivers? Or for getting over stumbling
> blocks? Is doing blackbox RE the only acceptable method of RE for Linux
> drivers? Would Sane accept my code if I decompiled the driver? Copyright
> issues? There shouldn't be any, since I'll not be seeing actual original
> source code.

You dont need to decompile. Search mailing list archives for genesys,
and google for datasheets. You will find plenty. then get some usb
sniffer logs, and use Pierre's tools as a base for interpreting them.

might also help to open the scanner and get the names off the chips,
particularly the GL chip and the AFE.

allan
-- 
"The truth is an offense, but not a sin"