Brightness control does not work on Ubuntu 20.04 LTS with Nvidia GeForce GTX 1660 Ti

Question

Got proprietary Nvidia drivers installed by Ubuntu itself, graphic card is recognized well by the system yet brightness control does not work when adjusted by either FN + F5/6 shortcut or by dragging brightness slider manually (keyboard shortcut triggers slider move as well, so it's heard by the system).

However: xrandr | grep " connected" | cut -f1 -d " " produces single output DP-2 and xrandr --output DP-2 --brightness 0.7 does change the brightness.

Googled a lot, tried various options, neither works to me. What can I do to make it work when dragging the slider as well?

Do you by any chance have `acpi=off` or `noacpi` in your grub boot parameters, which would have the effect of disabling your FN+function key controls? — Enterprise, Jun 06 '20 at 16:34
What does `ls /sys/class/backlight` reveal? On a laptop the hardware brightness is what FN keys control. Using `xrandr` is software control primarily used for external monitors not built in laptop displays. — WinEunuuchs2Unix, Jun 06 '20 at 16:52
@SerejaBogolubov See if this helps: [nvidia backlight brightness problem](https://askubuntu.com/questions/935585/nvidia-backlight-brightness-problem) — WinEunuuchs2Unix, Jun 06 '20 at 17:11

score 7 · Accepted Answer · answered Jun 07 '20 at 08:36

7

So, finally - after trying lots and lots of options - following helped me: At the /usr/share/X11/xorg.conf.d folder find file related to your nvidia and append following section:

Section "Device"
    Identifier "Device0"
    Driver "nvidia"
    VendorName "NVIDIA Corporation"
    BoardName "<your graphic card as it named in your system>"
    Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

You can find the name of your graphic by searching for "system" in your Ubuntu. In my case it is GeForce GTX 1660 Ti so in abovementioned configuration file it gonna be BoardName "GeForce GTX 1660 Ti" - enclosed in doublequotes.

Save and reboot.

answered Jun 07 '20 at 08:36

Zazaeil

257
2
9

Thank you! That one worked for me. Btw it worked both with and without the BoardName line for me. – Guillaume Perrault-Archambault Nov 14 '20 at 03:36
Very helpful, thanks a lot :) – Alen May 18 '21 at 20:21
@Sereja Bogolubov: IS this a Laptop or Desktop? – stephanmg May 30 '21 at 18:59
1

@stephanmg laptop – Zazaeil May 30 '21 at 19:42
I see, for regular monitors one can use the OSD panel of the monitor. – stephanmg May 31 '21 at 07:03
This didn't work for me, and it stopped my graphical interface from starting. After removing the contents above using a non-graphical tty, everything returned to normal (but I still cannot adjust brightness). – trisct Sep 17 '21 at 14:46

score 1 · Answer 2 · edited Jun 29 '21 at 00:26

Run nvidia-settings
Select X Server Display Configuration
Click Save to X Configuration File (don't click Save on opened dialog)
Click Show preview...
Copy Section "Device" ... EndSection (maybe you will need to copy Monitor and Screen sections)
Create file /usr/share/X11/xorg.conf.d/10-nvidia-settings.conf and paste copied text in it, add to Device section Option "RegistryDwords" "EnableBrightnessControl=1", save file
Add to file /etc/initramfs-tools/modules
```
nvidia
nvidia-drm
nvidia-modeset
```
Run sudo update-initramfs -u
Restart

If you played with file /etc/default/grub than try to remove all acpi... settings from GRUB_CMDLINE_LINUX_DEFAULT=

Description about steps 7 and 8 is here

Brightness control does not work on Ubuntu 20.04 LTS with Nvidia GeForce GTX 1660 Ti

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