Qt ignores input devices created after qmlscene has been launched

[Christopher Lee]

(text extract from an email)
We're having an interesting issue with the pinch touch gesture in autopilot that seems to be related to the recent upgrade of Qt.

I've found that if I create a UInput device before launching qmlscene the pinch gesture works as expected, but if we create the UInput devices after it is launched no input is received in the sample qml app.
So it appears that qmlscene is ignoring touch inputs from a device created after it is launched.
This code was working with the previous version of Qt as well as works on Saucy.

I have put together an example script[1] that has a pass and a fail test. The only difference in the passing test is that it creates a UInput device before launching qmlscene (commented in the code).

To reproduce using this script (assuming autopilot is installed):
 - bzr branch lp:~veebers/+junk/pinch-gesture-failures && cd pinch-gesture-failures
 - autopilot run test_pinch_event.TestTouchEvent.test_will_fail
or
 - autopilot run test_pinch_event.TestTouchEvent.test_will_pass

[1] lp:~veebers/+junk/pinch-gesture-failures

[Launchpad Janitor (janitor)]

This bug was fixed in the package autopilot - 1.4+14.04.20140401-0ubuntu1

---------------
autopilot (1.4+14.04.20140401-0ubuntu1) trusty; urgency=low

  [ Thomi Richards ]
  * Make the --enable-profile option for all autopilot commands.
  * Refactor introspection code to make the vis tool call only
    asynchronous dbus calls.
  * Optimisations for print_tree method.

  [ Leo Arias ]
  * Added a window resize for the BAMF process helper.

  [ Christopher Lee ]
  * Move functionality out of __init__.py
  * Add workaround for bug lp:1297592 by creating Touch device in
    AutopilotTestCase setUp. (LP: #1297592)
  * Fixes some functional tests that were failing on the devices. (skip
    Gtk, use desktop file hint for the qt one).

  [ Max Brustkern ]
  * Move functionality out of __init__.py
  * Additional pep257 changes.
 -- Ubuntu daily release <email address hidden> Tue, 01 Apr 2014 01:30:45 +0000

[Timo Jyrinki (timo-jyrinki)]

Could it be checked if this got better with Qt 5.3 in utopic? There were a lot of XInput2 / etc changes at least.