New approach to multitouch using DIDs and bitmasked events

[Henrik Rydberg]

Peter Hutterer wrote:
> 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:
>>>> -----BEGIN PGP SIGNED MESSAGE-----
>>>> Hash: SHA1
>>>>
>>>> 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.

Oh, that would be nice. Not saying I would do anything with it, but I am
curious. :-)

Thanks,
Henrik