I have an Nvidia GeForce GTX 970M card on my Ubuntu 20.04 laptop and I am using the driver nvidia-driver-395. The brightness in Ubuntu itself (outside ET) works fine, so the brightness controls on the keyboard work perfectly when I am using Ubuntu not in ET. In ET the brightness calibration slider offered by the game has no effect and neither the keyboard brightness controls, and the game is very dark. How can I make brightness work inside ET and why is it not working with nvidia drivers? I tried also with older Nvidia drivers, like 470 and 390 and they behave exactly the same.