According to this xfce documentation and here in the ArchWiki there is a hidden setting in xfce-power-manager
to specify a minimum brightness level.
- Run
xfce4-settings-editor
in terminal - Click on
+ Add
and enter
- Property:
/xfce4-power-manager/brightness-slider-min-level
- Type:
Int
- Value: e. g.
5
-OR- completely via cli
xfconf-query -c xfce4-power-manager -p /xfce4-power-manager/brightness-slider-min-level -t int --create -s 5
where -s 5 being an example minimum value of “5”.
Disclaimer: This could be a hardware-specific solution. I’m currently nowhere near a xfce desktop and can’t test the above.