I run a current unstable system (plasma-workspace 4:5.4.3-2) and I get this crash almost every time I try to suspend my notebook (1280x800 screen) with my external monitor (1920x1080) connected. It's not with big statistics, but I noticed that when I had the external monitor mirror the notebook screen (i.e. also set it to 1280x800) it didn't crash.
Michael
What's particularly bad is that the entire plasma session is killed and I'm thrown back to the login screen. So we are talking about data loss here.
The top of the backtrace is identical to the latest one in the bug report
#6 0x00007fadc79514de in QXcbScreen::mapToNative(QRect const&) const () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#7 0x00007fadc7956713 in QXcbWindow::mapToNative(QRect const&, QXcbScreen const*) const () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#8 0x00007fadc7957f8b in QXcbWindow::propagateSizeHints() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#9 0x00007fadc795d14c in QXcbWindow::setGeometry(QRect const&) () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#10 0x00007fadda10a91f in QWidgetPrivate::setGeometry_sys(int, int, int, int, bool) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#11 0x00007fadda10b4d0 in QWidget::setGeometry(QRect const&) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#12 0x00007faddb688f8a in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007fadda1294a1 in QDesktopWidget::screenCountChanged(int) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#14 0x00007fadda12a8ba in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#7 0x00007fadc7956713 in QXcbWindow::mapToNative(QRect const&, QXcbScreen const*) const () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#8 0x00007fadc7957f8b in QXcbWindow::propagateSizeHints() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#9 0x00007fadc795d14c in QXcbWindow::setGeometry(QRect const&) () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#10 0x00007fadda10a91f in QWidgetPrivate::setGeometry_sys(int, int, int, int, bool) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#11 0x00007fadda10b4d0 in QWidget::setGeometry(QRect const&) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#12 0x00007faddb688f8a in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007fadda1294a1 in QDesktopWidget::screenCountChanged(int) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#14 0x00007fadda12a8ba in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
