I have an old laptop, oldtimer linux fellow, and updated it to xubuntu 18.04.
After some sleep/resume problems with the proprietary nvidia-340 driver, I decided to try the nouveau. Sleep/resume ok. But there is a new problem: the brightness.
Using the proprietary driver, with
Option "RegistryDwords" "EnableBrightnessControl=1" in the
xorg.conf, the Fn-bright-up and Fn-bright-down keys work out of the box.
With the nouveau driver they don't.
$ ls /sys/class/backlight/
As expected nothing can be done using
But, surprise! The
nv_backlight is working:
$ echo 20 | sudo tee /sys/class/backlight/nv_backlight/brightness
But I don't know how to make my friend xfce knows that the Fn-bright-up and Fn-bright-down should talk with
/sys/class/backlight/nv_backlight/brightness instead of