Additional testing: Adding "acpi_osi=" (without quotes) with nothing after the equal sign to the GRUB_CMDLINE_LINUX_DEFAULT line in /etc/default/grub makes the brightness keys work complete with 10 levels of brightness. However, the notification no longer works.
Also, connecting and removing the AC adapter does not change the brightness, even though power management is set to do so. Curiously, hitting brightness up key after unplugging the AC adapter drops the brightness to 20%, suggesting the power management tried to set the brightness value, but it didn't actually change the value. The opposite happens when plugging back into AC. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693942 Title: Acer Aspire 5742Z No Screen Brightness Control -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs