[sane-devel] Lexmark 74 - first results

stef stef.dev at free.fr
Mon Nov 1 06:57:57 UTC 2010

Le Monday 01 November 2010 00:49:58 Torsten Houwaart, vous avez écrit :
> Hello,
> > If you double checked the X74 is rts8852 based, you can send patches to
> the mailing list for the lexmark backend.
> How can i make sure ?
> I've had some very promising results. I was able to get scans at 75dpi
> greyscale and colour. So I guess that means it is rts8852 based. Right?
> I had to adjust just a few registers which -I think- regard the scanner.
> But I had to change quite a lot of registers for the motor. The registers
> 0xe0 - 0xef are described in lexmark_low.c as "motor curve stuff". When I
> used register settings that all the other Lexmark models use the scanner
> head wouldn't start moving. So I used register settings for 0xe0-0xef I
> found by a whole page scan sniff in Windows. Could somebody explain to me
> how these registers work ?
> Especially: How universal are they. Can I just sniff the windows driver for
> all the different resolutions (75, 150, 300, 600) dpi for the two modes
> (gray, colour)? There is also a scanner mode where just the scanner head
> is moving with no light, must this have different motor curve settings ?
> best regards,
> Torsten

	unfortunately, there is no datasheet for rts8852 ASIC. So the meaning of 
each register has to be guessed from its usage in USB logs. Comparing values 
for scans at different resolutions is the right thing to do. Sometimes we 
can't have enough different values to figure out precisely the meaning of 
	For different models supported in the lexmark backend, there are 
different sensors and motors. So usually settings are shared if 2 models have 
the same motor.
	Light on/off shouldn't influence motor settings. However maybe when doing 
head parking, the light is turned off and the motor set for an higher cruising 
speed since there is no need to gather data from sensor.


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