← Back to team overview

touch-packages team mailing list archive

[Bug 1450137] Re: Qt5 applications crash when switching screens

 

FWIW, the screen switching problems are quite spread to a lot of smaller
bugs, which explains why Qt 5.4.2 did not fix everything.

For example, these bugs exist in upstream tracker:
https://bugreports.qt.io/browse/QTBUG-46024
https://bugreports.qt.io/browse/QTBUG-42985
https://bugreports.qt.io/browse/QTBUG-47041

A lot of rework to the code in question has happened in Qt 5.5, and now
5.5.1. Qt 5.5.1 is not yet released, but will be targeted to land to
Ubuntu after 15.10 release.

-- 
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to qtdeclarative-opensource-
src in Ubuntu.
https://bugs.launchpad.net/bugs/1450137

Title:
  Qt5 applications crash when switching screens

Status in qtdeclarative-opensource-src package in Ubuntu:
  Fix Released
Status in qtdeclarative-opensource-src source package in Wily:
  Fix Released

Bug description:
  # Impact
  When switching screens (e. g. when putting the laptop onto the docking station the notebook screen is turned off and the external one is turned on) Qt5 applications (including plasmashell) quite often crash.

  # Test Case
  * Have two screens. One plugged-in one not
  * Run plasma 5
  * Plug-in second screen and wait 10 seconds
  * Unplug and wait 10 seconds
  * Plug-in and wait 10 seconds
  * Unplug and wait 10 seconds
  * ...

  # Regression Potential
  Worst case scenario an application using qquickscreen would slow down because of erroneous screen change singals being emitted too often per second. This would however only reveal a lower level issue in the foundations that ultimately needs to be fixed anyway. 

  # Other Info
  The upstream code review [1] explains the issue and solution pretty well.

  https://codereview.qt-project.org/#/c/111100/

  
  --------- original report ---------------

  When switching screens (e. g. when putting the laptop onto the docking
  station the notebook screen is turned off and the external one is
  turned on) Qt5 applications (including plasmashell) quite often crash.
  This makes my laptop unusable, since I do that very frequently.

  The problem has already been described here: https://bugs.kde.org/show_bug.cgi?id=341497
  Apparently it is fixed in Qt 5.5

  I am running Kubuntu 15.04 64bit and libqt5gui5 5.4.1+dfsg-2ubuntu4.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/qtdeclarative-opensource-src/+bug/1450137/+subscriptions


References