Found a workaround for my Toshiba Tecra A11: http://ubuntuforums.org/showthread.php?t=2275437&p=13272746#post13272746
TL;DR edit /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_backlight=vendor" -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1462221 Title: Display Brightness Cannot be Changed Status in linux package in Ubuntu: Incomplete Bug description: I am using HP Probook 450 G0...It uses dicrete graphics (Intel GMA + AMD Radeon). I installed UbuntuMATE (DEsktop Env version 1.8.1). Under power management preferences the screen brightness cannot be changed no matter what value you set on the slider. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1462221/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
