Found one easy solution (a least on Ubuntu 20.04) to implement manually solution by changing grub configuration.
Edit /etc/default/grub To the parameter GRUB_CMDLINE_LINUX_DEFAULT add "acpi_backlight=vendor" The line should be GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor" update grub sudo update-grub reboot Don't know how to implement this in ubuntu distribution. Is it possible to create specific grub config during the installation process ? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
