[sane-devel] experimental/genesys backend status update

[svoltz@wanadoo.fr]

        Hello,

        experimental genesys backend after checkin last updates is now close to
be finished for at least MD5345/MD6471 scanner:

	- 50, 100, 150, 200, 300, 600 and 1200 dpi color and gray level
          8 bits scans are working reliably
	- is already usable in xsane for varoius scans at various dpi

        Current issues I am currently aware are:

        1 - quality image issues:
		- pictures are a little too red	
		- seems gain should depend on exposure time
		- picture are a little to dark 

	2 - USB issues:
		- there are bandwidth issues that lead to backtracking at high
		  dpi scans
		- usb read hangs sometimes when reading scan's data in 
		  genesys_search_start_position() . It may be related to
		  anything, and is quite mysterious.

	Features that are can be added quite easily:
	- lineart scanning
	- 16 bits scanning
	- scan resolution where motor dpi is not a round factor of CCD dpi
	  such as 250, 350, 400, 450, ... genesys_shrunk_line is currently
	  buggy.

	I'm about to start code cleanup so that the backend can head to inclusion
in sane-backends. Which, I think shouldn't take a long time.

Regards,
        Stef