Ubuntu can't adjust the brightness when using the independent display/nvidia graphics card

Due to driver compatibility issues, the open source graphics card driver cannot be used directly, and only the closed source Nvidia driver can be used. As a result, the screen brightness cannot be adjusted. The solution is as follows:

Method 1: Use Brightness-controller (simple, but not the root cause)

sudo add-apt-repository ppa:apandada1/brightness-controller
sudo apt-get update
sudo apt-get install brightness-controller-simple

Method 2: Adjust system configuration to achieve brightness control (recommended)

Make sure the Nvidia discrete graphics driver is installed

It can be installed in Ubuntu's Softwares center, or it can be installed using the command line.

If it is found /sys/class/backlightto be empty by accident (it should have content normally), proceed to the following steps.

Revise/etc/default/grub

ps: I am using the Sublime editor, so yes subl, if you are used to gedit, please change accordingly gedit.

sudo subl /etc/default/grub

Bundle

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

change into:

GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash acpi_osi=Linux”
GRUB_CMDLINE_LINUX="acpi_backlight=vendor“

save, thenupdate-grub

sudo update-grub

After restarting, it is found that the brightness cannot be adjusted, but the brightness icon will appear after pressing the shortcut key.

modified 10-nvidia.confconfiguration

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

Add Option "RegistryDwords" "EnableBrightnessControl=1"it in, for example, my modification is:

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

modify /etc/modprobe.d/blacklist.conf, disable*labtop

sudo gedit /etc/modprobe.d/blacklist.conf

Add at the end of the file:

blacklist dell-laptop

The keywords of different brands are different, mine is dell, corresponding dell-labtop, part of the association is ideapad_laptopthat different brands can use sudo find /sys/ -type f -iname '*brightness*' | grep labtopto view the corresponding keywords ( labtopjust see the words).

latest updateupdate-initramfs

sudo update-initramfs -u

Then restart the computer.

If it still doesn't work, follow the steps

sudo subl /etc/initramfs-tools/modules

Add the following at the end:

nvidia
nvidia-drm
nvidia-modeset

Finally update update-initramfs, then restart the computer, try to adjust the brightness shortcut key, everything is ok.

sudo update-initramfs -u

regret medicine

If after using any of the above steps, the boot is stuck on any interface, it means that there is a problem with the configuration, use the following steps to restore the modified configuration file:

Power on Esc, then select Adavance ...that item (the second item?), then select ...(recovery mode), and then select ...root, a command line interface will appear, use vim to restore the modified file, then execute sudo update-grubor sudo update-initramfs -u, and finally rebootrestart.

reference: