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I'm new to Linux, so I use Linux on dualboot. At the first time of installing Ubuntu, the brightness slider was working fine but when I made some updates + installed an Nvidia driver the slider is not doing anything anymore. Tried adding GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor to /etc/default/grub but didn't work. Tried to install Brightness Control as a temporary solution but even that wasn't working. The /sys/class/backlight folder has two folder in it; amdgpu_bl0 and ideapad, brightness slider only effect the files included in ideapad folder. What should I do? System specs: Ryzen 5 4600H GTX 1650 Ti

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    I have a similar issue. From what I read, you may try to revert Nvidia driver to version 470 if you are using 510. Personally I cannot afford it because 470 is not working properly when 2 external monitors are plugged.
    – milembar
    May 8, 2022 at 21:05
  • Reverting to old drivers and / or reverting xorg drivers didn't work for me. You may try the answer i posted but if you are not using an iGPU that might not solve you are problem.
    – Reimner
    May 9, 2022 at 22:37

6 Answers 6

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Thanks to this post, I am able to change the screen brightness. Go to /etc/grub and find GRUB_CMDLINE_LINUX= and add amdgpu.backlight=0 to there. Solved my issue in Fedora and Kubuntu both so the problem is the Radeon Graphics iGPU I guess.

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    thank for the advice, sadly I have an intel CPU so it is not going to help for me. Glad you found a solution to your problem!
    – milembar
    May 10, 2022 at 5:19
  • Thanks, i hope you can find a solution cuz this thing kills peoples eyes. Good luck!
    – Reimner
    May 11, 2022 at 16:29
  • milembar, I also have intel CPU and graphics, have you found any other way? the most weird thing is slider is working but buttons are not working
    – Kiran Mali
    Aug 24, 2022 at 6:18
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I had the same issue and the same fix as the accepted answer, but I just wanted to clarify the steps because it was confusing when I tried to follow them.

1). Open /etc/default/grub in a text editor with sudo permissions for example sudoedit /etc/default/grub

2). Add amdgpu.backlight=0 to the line GRUB_CMDLINE_LINUX="..."

2). Run sudo update-grub

3). Reboot

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Tried the solutions above, but none of them working on my Nvidia GPU/intel core i.7 CPU, Ubuntu 22.04 machine with wayland. After updating the module nvidia-dkms the brightness control worked again:

sudo apt install nvidia-dkms-525
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  • Few months ago the following helped me GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor". However, last week it stopped working. Installing nvidia-dkms-525 package helped! Mar 1 at 14:57
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I deleted the nvidia drivers. Then I installed the nvidia drivers. Then, hey presto, the sliders in brightness-control started working again.

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Just wanted to share that I tried a plethora of methods related to the grub configurations without any success, but I managed to solve this issue by simply updating the linux kernel. I had linux 22.04 LTS kernel 5.15 and updated it to 5.19.11-051911-generic.

My machine had 2 directories under /sys/class/backlight: amdgpu_bl0 and nvidia_0 and I was able to manually change the brightness value in the /sys/class/backlight/amdgpu_bl0/brightness with sudo. At first I thought it was because of the NVIDIA drivers but after uninstalling them the problem persisted. After the kernel update I no longer had the nvidia_0 folder in the /sys/class/backlight.

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    While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. - From Review
    – Pilot6
    Oct 2, 2022 at 10:36
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https://github.com/F-i-f/soft-brightness seems to be the only solution that works for (AM)OLED screens running on Wayland with Intel processor.

After installing soft-brightness, brightness gets adjusted via both Ubuntu control and keyboard.

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