diff -up qtbase-everywhere-src-5.12.1/src/plugins/platforms/xcb/qxcbscreen.cpp.hidpi_scale_at_192 qtbase-everywhere-src-5.12.1/src/plugins/platforms/xcb/qxcbscreen.cpp

--- qtbase-everywhere-src-5.12.1/src/plugins/platforms/xcb/qxcbscreen.cpp.hidpi_scale_at_192	2019-02-03 13:21:27.866906481 -0600

+++ qtbase-everywhere-src-5.12.1/src/plugins/platforms/xcb/qxcbscreen.cpp	2019-02-03 13:23:47.554767565 -0600

@@ -744,7 +744,7 @@ void QXcbScreen::updateGeometry(const QR

     // Use 128 as a reference DPI on small screens. This favors "small UI" over "large UI".

     qreal referenceDpi = physicalSize().width() <= 320 ? 128 : 96;

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

+    m_pixelDensity = qMax(1, (int) (dpi/referenceDpi)); //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);