[sane-devel] Plans for an updated avision backend (HP7400+HP5300+Minolta Scan Dual II+???)

[Rene Rebe]

Hi.

On Sun, 11 Nov 2001 18:34:09 +0000
Jose Paulo Moitinho de Almeida <moitinho@civil.ist.utl.pt> wrote:

> Hello
> 
> Following my previous mail to the list I received some info, which may be 
> "just what we want".

Do you mean the infos from me - or additional ones?

> Those interested in participating in the development/testing of the avision 
> backend, so that it can use the scanners that are known to be manufactured by 
> avision, but are not supported by the current backend, please contact me. 

I took a deeper look into it last night: The color line difference can be found
in bytes 53-59. But I do not know where the dark to full-scale gradient stripes
come from. I only fill the half of the gamma-table (2048 of 4096 entries) - because
more is not needed. Maybe the scanners generate values in this range to make it
possible for the driver to calibrate s.th. (heavily guessed ...)??

> I think that we should prepare a structure to enable some kind of shared 
> development. Good ideas to achieve this are welcome and, as usual, someone 
> with lots of time to spare would be most usefull.... perhaps then we could do 
> without the list....

I would also be willing to adapt the code. (Also I have not that more time ...).
Do you have additional information?

btw. My AV630CS leaves most of the SCSI inquiry 0 ... - so I never had a chance
to see all this entries ;-(. - So we need to add some more internal _states_ to
handle all this variants of parameters ...

Some people have stated that my backend keeps the kernel-module crashing - this
doesn't seem to be true. As far as I can see the avision-backend's problem is only
to do some color-channel correction and gamma-table computing. So the kernel-module
should also be reviseted to not crash. (And even if my backend write imperfect
combinations of bits, the kernel should not crash anyway).

> The scanners in question are (please correct):
> 
> - HP 7400
> - HP 5300
> - Minolta Scan Dual II
> - .....
> 
> I just wonder if there are no "real" avision scanners that need/could benefit 
> >from an updated backend.

None I know of (they do not sell USB scanners themselfes).

> Regards
> 
> Ze Paulo
> 
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k33p h4ck1n6 René

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René Rebe (Registered Linux user: #127875 <http://counter.li.org>)

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