[sane-devel] xerox_mfp usb malfunction

[m. allan noah]

2011/3/9 Warren Turkal <wt at penguintechs.org>:
> 2011/3/9 ABC <abc at telekom.ru>

>  What i think should actually happen is that sanei should have it's own
> method for dealing with usb (and other busses) in whatever form it takes
> (e.g. /dev/scanner dev file or libusb or scsi device or whatever). Sanei
> should call any callbacks into the backend with a generic form for the bus
> type instead of exposing it's innards. Assuming that a string is the best
> form for that generic form, something like "usb:vendor_id:product_id" is
> probably reasonable.

...

And that suggestion does not deal with two identical scanners attached
to the machine. And the 'struct' version with a single callback
requires us to use enum every possible transport thru a single
function in sanei, which breaks down with a backend specific
transport.

If a backend supports multiple transports, it can use multiple
callbacks (or callback wrappers) which set the transport in the
scanner struct, in addition to the opaque string. Now, this breaks
down if two different transports use the same name, or if a backend
treats the string as non-opaque. Though the last might be required in
the case of a scanner which cannot be auto detected, like a tcp
machine. I think that's the case here?

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