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/
returns acpi_video0
and nv_backlight
.
As expected nothing can be done using acpi_video0
.
But, surprise! The nv_backlight
is working:
$ echo 20 | sudo tee /sys/class/backlight/nv_backlight/brightness
works!
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 /sys/class/backlight/acpi_video0/brightness
.
Thank you.
Best Answer
The nouveau driver now (some time ago it didn't) creates the
/sys/class/backlight/nv_backlight
and it works. So passingacpi_backlight=vendor
to the kernel disables the/sys/class/backlight/acpi_video0
. Withoutacpi_video0
, thebacklight_helper_get_best_backlight()
will return the nv_backlight out of the box.So, open /etc/default/grub, edit:
Save and
sudo update-grub
.