[PATCHv2] evdev: add 3x3 transformation matrix xinput property for multi-head handling

[Peter Korsgaard]

>>>>> "Simon" == Simon Thum <simon.thum at gmx.de> writes:

 Simon> Hi all,
 >> For absolute input devices (E.G. touchscreens) in multi-head setups, we
 >> need a way to bind the device to an randr output. This adds the
 >> infrastructure to evdev to allow us to do so.

 Simon> I like the idea, but just if you haven't considered it: more or
 Simon> less the same thing could be done in dix (GetPointerEvents),
 Simon> where it would stand a remote chance to sync with randr, if
 Simon> desired. Also, in dix one would have more control when creating
 Simon> synthetic events, properly do Xi2 raw/screen coords etc.

That was also my first idea, but I discussed it with Peter on IRC, and
he preferred to keep it outside the server - to not hardcode any policy.

With the current implementation we just have the most basic
infrastructure in evdev, and the policy of how to handle touchscreens
(and figuring which ones are connected to what randr outputs) is outside
- I'm looking into adding support for it in gnome-display-properties now.

I would furthermore like to support existing customers with
touchscreens, and it is simpler to just get them to bump evdev than
updating the server on whatever distribution they might be using.

Thanks for your input.

-- 
Bye, Peter Korsgaard