Display questions - resolution and firmware for backlight

There are no solutions to my question available yet on the forum. Settings Manager → display only has one resolution available. It cant be changed from there. Changing values in Settings Editor has no effect. No one answered if this could be done by changing boot parameters…

Is there a way to go to Dom0 terminal and change, for example, a 1920×1080 to 1600×900 or 1280 × 720 (same 16:9 ratios).

Why doesnt increasing the values in Settings Editor → xfce4-power-manager → brightness-level change anything?

Dom0 runs Fedora-32 with xfce, and it manages the graphics in R4.1. I am not sufficiently knowledgeable here, but I expect that Fedora-32- or xfce-specific troubleshooting should help here. Try searching some Linux forums…

Do you use NVIDIA?
Did you try to use xrandr to create, add and load new profile based on desired cvt?

Xandr is part of Dom0 but any size but the current is “not found in available modes” and minimum, current, and maximum are all the same. Xbacklight isn’t installed. There must be more primitive commands controlling display.

I’ve got Intel Mesa. What primary code directs the GPU and peripheral display?