Problem with touchscreen events and grabs

[Thomas Jaeger]

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 never filed a bug report for this, but I can if you want.

Tom