Handing Control of Sentelic Touchpads to Synaptics

[Éric Piel]

Op 19-07-10 18:29, David Regev schreef:
> Hello Eric,
> 
> I’ve seen in several places that the reason Sentelic’s driver doesn’t
> have edge scrolling is due to patent concerns. Perhaps absolute mode was
> overzealously removed for the same reason.
Yes, I've read about this as well. I know barely nothing about patents
but I would imagine that for the kernel driver, working in absolute mode
(and not translating anything to scrolling) should be very safe.  For
now I prefer to concentrate on the technical side than wondering how
many patents the synaptics driver is covering...

> Yes, I would love some help! If we can get this to work, do you think it
> will be possible to merge this upstream? I feel bad for all the people
> out there with this touchpad. Some have even gone as far as to remove it
> physically and replace it with an $8 one[*]. It would also be great to
> be able to say that this touchpad works better on Linux than on Windows.
I see no reason that the work wouldn't be merged upstream. That's
exactly what is happening with the elantech driver.

Actually, it should be pretty easy, as Sentelic has even sent a
description of the protocol in Documentation/input/sentelic.txt ! There
are 3 (quite similar) absolute protocols depending on the device.
Probably it's easy to distinguish which device is present by reading
some of the registers (eg: Product ID). One of the info is about the
"scroll buttons" pressed. Hopefully, when the finger is over these
areas, the X and Y coordinates are still normally reported, otherwise it
will be hackish at best :-S

The best to start is to have a git tree of the latest linus' kernel, and
to have it compiling for your machine... Then you can start modifying
drivers/input/mouse/sentelic.c .

Eric