After installing Ubuntu 18.04 LTS a new Dell XPS 7590 laptop with OLED display, the brightness is stuck at the highest point (the Fn+F11 or F12 commands show that the brightness is being changed, but no brightness change occurs).
I have tried many suggestions from the web, but all failed; e.g., changing the
acpi_backlight parameter values in
/etc/default/grub, creating an
xbacklightmon file, or installing brightness controller.
Is there any way that the brightness could be changed?