Problem with touchscreen events and grabs

[Peter Hutterer]

On Sun, Oct 28, 2012 at 03:38:44AM -0400, Thomas Jaeger wrote:
> On 10/22/2012 02:47 AM, Peter Hutterer wrote:
> > On Tue, Oct 16, 2012 at 09:54:23PM -0400, Thomas Jaeger wrote:
> >> I've noticed an issue with grabs as well, not sure if it's related to
> >> this one.  It's really easy to reproduce, though:  All you need is a
> >> little test client that passively grabs button 1 on the MD (like the one
> >> attached).  A passive core grab will do as well.  What happens is that
> >> (1) clients selecting for core events will receive emulated pointer
> >> events despite the passive grab and (2) sometimes ButtonRelease events
> >> go missing (this goes both for the grabbing and non-grabbing clients,
> >> but not necessarily at the same time).
> > 
> > btw, did you file a bug for this one? I've got a preliminary patch
> > (attached) but I'm not sure of the side-effects yet.
> > 
> > Cheers,
> >    Peter
> 
> Sorry about the late reply, I'm pretty swamped right now.  I've been
> using the patch in the last week and I haven't noticed any of the issues
> Timo described (but I don't run unity).  For multi-touch, the current
> behavior seems a little questionable, though: Any client selecting for
> touch events won't receive any events for the first touch point, but it
> will receive events for any subsequent touch points.  For touch grabs, a
> TouchBegin will be delivered for the second touchpoint, immediately
> followed by a TouchEnd.

I admit I still don't have a full set of test cases to test this properly,
got stuck on a few other things last week. I won't push for the patch to get
included though until I'm sure of the side effects.
 
> I never filed a bug report for this, but I can if you want.

yes, please, just so it's easier to track potential regressions.

Cheers,
   Peter