[SOLVED] Not able to reduce Laptop Brightness on Ubuntu 20.04

AayushBhan · 10-25-2020, 03:30 AM

I have a lenovo legion y540 with ubuntu 20.04 LTS on my ssd and windows on the hdd. I'm not able to change the brightness while in ubuntu. I've tried downloading the "Brightness Controller" but using it changes nothing.
I also tried following the following article - https://vitux.com/control-screen-brightness-from-ubuntu-terminal/

However from the above article the output given below for

Code:

xrandr | grep " connected" | cut -f1 -d " "

-

Quote:

xrandr: Failed to get size of gamma for output default
default

The output for

Code:

lspci|grep VGA

is -

Quote:

01:00.0 VGA compatible controller: NVIDIA Corporation TU117M [GeForce GTX 1650 Mobile / Max-Q] (rev a1)

I also tried

Code:

ls -l /sys/class/backlight

I got

Quote:

total 0
lrwxrwxrwx 1 root root 0 Oct 25 12:22 ideapad -> ../../devices/pci0000:00/0000:00:1f.0/PNP0C09:00/VPC2004:00/backlight/ideapad

I really need to be able to change the brightness. Any sort of help would really be appreciated. Since this is my first post I tried to give as much information as I could that came to my head, if anything else is required do let me know I would update it.

Thanks a lot.

beachboy2 · 10-25-2020, 11:28 AM

AayushBhan,

Welcome to LQ forums.

I think you need to create or modify the /usr/share/X11/xorg.conf.d/10-nvidia.conf file.

If you don’t already have gedit, then install it:

Code:

sudo apt install gedit

Open or create the file:

Code:

sudo gedit /usr/share/X11/xorg.conf.d/10-nvidia.conf

You then need to add this line, using copy & paste to avoid typing errors:

Option "RegistryDwords" "EnableBrightnessControl=1;"

The OutputClass section should then read:

Code:

Section "OutputClass"
    Identifier "nvidia"
    MatchDriver "nvidia-drm"
    Driver "nvidia"
    Option "AllowEmptyInitialConfiguration"
    Option "RegistryDwords" "EnableBrightnessControl=1;" 
    ModulePath "/usr/lib/x86_64-linux-gnu/nvidia/xorg"
EndSection

Click on Save.
Click on Close.

Then reboot.

AayushBhan · 10-25-2020, 01:11 PM

Hey BeachBoy,
I tried these steps but they don't seemed to have made any changes. I'm still not able to change the brightness of my screen.

Quote:

Originally Posted by beachboy2

AayushBhan,

Welcome to LQ forums.

I think you need to create or modify the /usr/share/X11/xorg.conf.d/10-nvidia.conf file.

If you don’t already have gedit, then install it:

Code:

sudo apt install gedit

Open or create the file:

Code:

sudo gedit /usr/share/X11/xorg.conf.d/10-nvidia.conf

You then need to add this line, using copy & paste to avoid typing errors:

Option "RegistryDwords" "EnableBrightnessControl=1;"

The OutputClass section should then read:

Code:

Section "OutputClass"
    Identifier "nvidia"
    MatchDriver "nvidia-drm"
    Driver "nvidia"
    Option "AllowEmptyInitialConfiguration"
    Option "RegistryDwords" "EnableBrightnessControl=1;" 
    ModulePath "/usr/lib/x86_64-linux-gnu/nvidia/xorg"
EndSection

Click on Save.
Click on Close.

Then reboot.

frankbell · 10-25-2020, 07:43 PM

Most of my laptops have had hardware keys or key combinations for adjusting the brightness.

What is the make/model of the laptop?

AayushBhan · 10-26-2020, 01:36 AM

Hey FrankBell,
My laptop does have keys specifically for changing the brightness, namely - Fn+F6. However, the brightness actually doesn't change even though it shows the status bar moving up and down.
My laptop is the Lenovo Legion Y540 (15) - GTX 1650 4GB Graphics.

Quote:

Originally Posted by frankbell

Most of my laptops have had hardware keys or key combinations for adjusting the brightness.

What is the make/model of the laptop?

AayushBhan · 10-26-2020, 05:17 AM

After a lot of searching around on askUbuntu, I stumbled upon this https://askubuntu.com/questions/1261722/llvmpipe-llvm-10-0-0-256-bits-is-getting-detected-instead-of-nvidia

I realized I was facing this issue as well, maybe this was the cause for the brightness not being able to work with your solution(IDK). So I figured might as well try to fix that first and I just ended up installing ubuntu all over again. I was still facing the brightness issue though the above problem was fixed.
Finally your solution worked with the new installation.

Thanks a ton beachboy2. This really helped me out.

Quote:

Originally Posted by beachboy2

AayushBhan,

Welcome to LQ forums.

I think you need to create or modify the /usr/share/X11/xorg.conf.d/10-nvidia.conf file.

If you don’t already have gedit, then install it:

Code:

sudo apt install gedit

Open or create the file:

Code:

sudo gedit /usr/share/X11/xorg.conf.d/10-nvidia.conf

You then need to add this line, using copy & paste to avoid typing errors:

Option "RegistryDwords" "EnableBrightnessControl=1;"

The OutputClass section should then read:

Code:

Section "OutputClass"
    Identifier "nvidia"
    MatchDriver "nvidia-drm"
    Driver "nvidia"
    Option "AllowEmptyInitialConfiguration"
    Option "RegistryDwords" "EnableBrightnessControl=1;" 
    ModulePath "/usr/lib/x86_64-linux-gnu/nvidia/xorg"
EndSection

Click on Save.
Click on Close.

Then reboot.