SUMMARY The QT_AUTO_SCREEN_SCALE_FACTOR environment variable is not set to 1 upon KDE startup. The issue seems to be specific to this particular env. variable: others from ~/.config/environment.d/*.conf are set as expected. STEPS TO REPRODUCE 1. Set QT_AUTO_SCREEN_SCALE_FACTOR=1 via ~/.config/environment.d/11-kde.conf 2. Logn to KDE 3. env | grep QT_AUTO_SCREEN_SCALE_FACTOR OBSERVED RESULT QT_AUTO_SCREEN_SCALE_FACTOR=0 EXPECTED RESULT QT_AUTO_SCREEN_SCALE_FACTOR=1 SOFTWARE/OS VERSIONS Linux/KDE Plasma: ubuntu 19.04 / 5.15.4 (available in About System) KDE Plasma Version: 5.15.4 KDE Frameworks Version: 5.56.0 Qt Version: 5.12.2 ADDITIONAL INFORMATION There seems to be nothing related to this variable in logs or configuration. This variable is absolutely essential for working HiDPI setup in multi-monitor configuration. The workaround is to set it via ~/.config/plasma-workspace/env/qt-fix.sh but that's ugly - the real fix would be to find out what exactly breaks setting this variable.
QT_AUTO_SCREEN_SCALE_FACTOR is deprecated since 5.14 > Added the QT_ENABLE_HIGHDPI_SCALING environment variable > which enables high-dpi scaling based on display DPI. > Replaces QT_AUTO_SCREEN_SCALE_FACTOR (now deprecated), > and corresponds to the Qt::AA_EnableHighDpiScaling application attribute. source: https://wiki.qt.io/New_Features_in_Qt_5.14
Yep, we don't use QT_AUTO_SCREEN_SCALE_FACTOR.