QObject::startTimer: Timers cannot be started from another thread

[Albert Astals Cid]

When blanking/unblanking the screen on the phone you get

QObject::startTimer: Timers cannot be started from another thread

It comes from
#0 0xffffffff in QObject::startTimer(int, Qt::TimerType) () at /home/phablet/chroot/home/phablet/qtbase-opensource-src-5.4.1+dfsg/lib/libQt5Core.so.5
#1 0xffffffff in QTimer::start() () at /home/phablet/chroot/home/phablet/qtbase-opensource-src-5.4.1+dfsg/lib/libQt5Core.so.5
#2 0xffffffff in MInputContext::hideInputPanel() () at /usr/lib/arm-linux-gnueabihf/qt5/plugins/platforminputcontexts/libmaliitphabletplatforminputcontextplugin.so
#3 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/qt5/plugins/platforms/libqpa-ubuntumirclient.so
#4 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/libmirclient.so.8
#5 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/libmirclient.so.8
#6 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/libmirclient.so.8
#7 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/libmirclient.so.8
#8 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/libmirclient.so.8
#9 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/libmircommon.so.3
#10 0xffffffff in () at /usr/lib/arm-linux-gnueabihf/libstdc++.so.6
#11 0xffffffff in start_thread () at /lib/arm-linux-gnueabihf/libpthread.so.0
#12 0xffffffff in () at ../sysdeps/unix/sysv/linux/arm/clone.S:89

This means basically that the start() call to the timer in MInputContext::hideInputPanel is being ignored

Can be "relatively" easily fixed in two ways:
 * Make the sipHideTimer.start(); in MInputContext::hideInputPanel be a QMetaObject::invokeMethod
 * Make the integration->inputContext()->hideInputPanel(); call in aboutToStopCallback be a QMetaObject::invokeMethod to QInputMethod::hide

The question is though if this actually needs fixing since there seems to be nothing broken? So maybe removing the integration->inputContext()->hideInputPanel(); call in aboutToStopCallback is the actual fix?