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ETA: I installed third part software from the beginning.

I've updated the Intel drivers:

sudo add-apt-repository ppa:ubuntu-x-swat/updates
sudo apt-get update
sudo apt-get upgrade
sudo apt install mesa-utils

After restarting the computer:

glxinfo | grep "OpenGL version" glxgears

The information shown by Terminal seems to be OK, but still the brightness control doesn't work.

Hope everyone is doing fine. I've recently upgraded my laptop, Ubuntu 14.04 LTS to Ubuntu 20.04 LTS. I've installed Unity Desktop and have realized that the brightness control (System settings - Brightness & Lock) is not working. When I try to change the brightness using the bar, nothing changes.

Does anyone know how to solve it?

Eliah Kagan
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Jack
  • 33

5 Answers5

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I had the same problem & it's caused by Nvidia graphics.

Did you install " third party software " in OS installation ?

You can try to delete your not recognized graphics, but more easy is a fresh new OS installation and let system choose right drivers. Install via sudo apt install ubuntu-restricted-extras , however if it won't enough to completely purge files and paths, much easy is reinstall OS. Nothing other works for me. Feel free to choose Normal or Minimal installation in first step of this window.

enter image description here

Em Vo
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How annoying it is if the brightness control doesn't work? Pretty annoying! There's a simple solution, which I tried and worked out well.

Go to 'Software & Updates' --> choose 'Additional Drivers' there you can find NVIDA Corporation binary driver and below that open source. You have to choose the open source. Ta-da!

screenshot of Additional Drivers in Software & Updates

Eliah Kagan
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Karthik
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If you are running Nvidia (which your question did not clearly state) the best results are using the proprietary drivers (you can select and install them via the Hardware app, if not already done so) But that driver doesn't allow you to set the brightness by default. But this solution worked on my thinkpad:

! This will only work with the proprietary NVIDIA drivers !

create /etc/X11/xorg.conf.d/21-Nvidia.conf by opening an editor with sudo (open a terminal):

sudo mkdir -p /etc/X11/xorg.conf.d/
sudo nano /etc/X11/xorg.conf.d/21-Nvidia.conf

Copy this code into your editor:

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    Option         "RegistryDwords" "EnableBrightnessControl=1"
EndSection

Save it with Crtl+X.

Restart. Then it should work

kanehekili
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0

A friend of mine found the solution.

Edit grub:

sudo gedit /etc/default/grub

Find this line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

Change it for this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Save and close.

Update GRUB:

sudo update-grub

Restart the computer.

Eliah Kagan
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Jack
  • 33
0

What it helped me was the first answer to this question, but I'm going to add some extra things I had to do, here are the steps:

1º Go into the menu and click in "Software and Updates" app and go in additional drivers. It should look like this.

Software and Updates -> Additional Drivers

2º From all the options choose the latest one (the one that has the greater number) and you'll see that there are lots of the, some end in -server, others end in -open; what you have to do is choose the one that ends in nothing, for example, in the picture above I used the first one 'Using NVIDIA ... nvidia-driver-535 (propietary)' and then I clicked on apply changes, it made me restart and voila!

Note: If the screen has chosen the option 'Continue using a manually installed driver' what you have to do is execute this command:

sudo apt purge nvidia-*

and reopen your 'Software and updates' app and it should work.

Aissa Rouk
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