New approach to multitouch using DIDs and bitmasked events

[Peter Hutterer]

On Tue, Jul 06, 2010 at 08:29:34AM +0200, Henrik Rydberg wrote:
> Peter Hutterer wrote:
> > On Sat, Jul 03, 2010 at 01:10:24AM -0400, Rafi Rubin wrote:
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> >> On 07/02/10 05:59, Henrik Rydberg wrote:
> >>> Peter Hutterer wrote:
> >>> [...]
> >>>> It'd be interesting to see how much work it is to have this API
> >>>> _replace_ the current API. Gives us more exposure and better testing.
> >>>> Note that I have some more API changes planned (not coded) that simplify
> >>>> the init process, they should all go in in one go.
> >>>> Another change that goes with that is the ability to easily split up
> >>>> devices into multiple X devices. This would make it easier to handle
> >>>> devices that have both MT events and normal events - they would simply
> >>>> end up being two devices, one normal one, one DID.
> >>>>
> >>>> Henrik, Rafi - do you think this would work for the MT devices we've
> >>>> seen so far?
> >>> From a device perspective, absolutely. In the kernel, a single device can have
> >>> any combinations of BTN, ABS, and MT events. Keys are getting there as well, but
> >>> are still normally separated by force. In other words, trusting the kernel to
> >>> make a logical split of events which fits the X framework is not very fruitful.
> >>>
> >>> Going forward, I wonder why we split input into separate devices at all. We have
> >>> different types, and different behavior based on capabilities, but input is
> >>> becoming so intermixed that the notion of separated devices looses its meaning.
> >>> Why not just put all input events into the same bucket, and let clients specify
> >>> what event types to listen to?
> >> I agree, I don't see the need to artificially separate keyboards and pointers.
> > 
> > say hello to my friend the core protocol. approximately 100% of all
> > applications rely on it (rounded to the nearest percent) :)
> > who needs enemies if you got friends like this.
> > 
> > fwiw, about a year ago I had a private branch that gets rid of the
> > pointer/keyboard distinction and provide a unified master device that's both
> > pointer and keyboard. that didn't turn out well, grab synchronization is a
> > nightmare.
> 
> I will take your word for it, but it does sound like there is not much of a
> resistance against the idea. :-)

I can give you the branch if you're really interested but it didn't get
further than a lot of search/replace of inputInfo.pointer and
inputInfo.keyboard. When I started sorting out how a single master device
may be grabbed sync on the keyboard but async on the pointer with different
replaying order or sync/async swapping I gave up.

Branch date's back to march 2009, so it's a bit out of date.

Cheers,
  Peter