Package: libqt5waylandclient5
Version: 5.15.8-2
Native Wayland Qt5 applications with touchscreen support have a nasty tendency
to segfault while receiving touch input, especially when one is trying to write
using a stylus as the palm also makes contact with the touchscreen. This issue
has only been recently fixed in Qt 6.7 and as far as I know there is no
upstream fix at the moment for Qt 5.15. An if statement (highlighted with
pointer arrow) is added to function QWaylandInputDevice::Touch::touch_frame()
in qwaylandinputdevice.cpp in Qt 6.7 to fix the bug:
if (mFocus) {
// Returns a reference to the last item in the list. The list must not
be empty.
// If the list can be empty, call isEmpty() before calling this
function.
// See: https://doc.qt.io/qt-5.15/qlist.html#last
-> if (mPendingTouchPoints.empty())
return;
const QWindowSystemInterface::TouchPoint &tp =
mPendingTouchPoints.constLast();
I encountered the issue using MrWriter, compiled from source, on Ubuntu 22.04
(linked against Qt 5.15.3). Said issue was severe enough in my experience to
interfere with day-to-day activities. As Ubuntu is downstream to Debian, I
thought it would be better if I report the bug here.
