--- qtbase-opensource-src-5.7.1/src/plugins/platforms/xcb/qxcbscreen.cpp~

+++ qtbase-opensource-src-5.7.1/src/plugins/platforms/xcb/qxcbscreen.cpp

@@ -750,7 +750,7 @@ void QXcbScreen::updateGeometry(const QR

         m_sizeMillimeters = sizeInMillimeters(geometry.size(), virtualDpi());

     qreal dpi = geometry.width() / physicalSize().width() * qreal(25.4);

-    m_pixelDensity = qMax(1, qRound(dpi/96));

+    m_pixelDensity = qMax(1, (int)(dpi/96)); // instead of rounding at 1.5, round at 2.0 (same as GNOME)

     m_geometry = geometry;

     m_availableGeometry = geometry & m_virtualDesktop->workArea();

     QWindowSystemInterface::handleScreenGeometryChange(QPlatformScreen::screen(), m_geometry, m_availableGeometry);