[Xcb] [RFC v0 proto] Add XInput2 protocol description

[Daniel Martin]

(In the following I'll write "XI2" when I mean the XInput extension
starting with version 2.0 and "XI" for the version up to 1.5.)

On Mon, Dec 03, 2012 at 09:56:26AM -0500, Peter Harris wrote:
> On 2012-12-02 16:05, Daniel Martin wrote:
> > Add the XInput2 protocol description for reviewing and feedback.
> 
> I haven't had time to review the meat of this, but this stuck out on an
> initial glance:
> 
> > +	xinput2.xml \
> 
> > +<xcb header="xinput2" extension-name="Input2"
> > +     extension-xname="XInputExtension" major-version="2" minor-version="2">
> 
> That's the same extension-xname as xinput.xml. I suspect the new
> definitions should be in xinput.xml, not in their own file.

I've choosen to make it in a seperate file, cause the extension name is
nearly the only thing both versions have in common and XI2 superseeds
the functionallity provided by XI.

Supporting both versions is not necessary as the XI specification
states:
    "... New clients are discouraged from using this protocol
         specification. Instead, the use of XI 2.x is recommended. ..."

Mixing both versions in one file would cause to much confusions on the
(library) user side, as he wouldn't know which request is for which
version without having a look at the specification.

Due to that, the fact that the protocol description for XI is not
complete and XI is disabled by default in libXCB, I would rather mark it
as deprecated when this XI2 protocol description becomes usable. But, I
wouldn't like to merge them.