Sunday, December 21, 2014

Lenovo Yoga 13 and Screen Brightness On Fedora 21

Just upgraded to Fedora 21 and the screen brightness controls do not work in Gnome.

Before Fedora 21 I had modified the following variable GRUB_CMDLINE_LINUX in the default grub file: /etc/default/grub in order to append `acpi_backlight=vendor`

#emacs /etc/default/grub

GRUB_CMDLINE_LINUX="...existing vars here... acpi_backlight=vendor"

After the upgrade I had to change this from acpi_backlight=vendor to acpi_backlight=intel. Once the file is updated run:

#grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg

Once done, reboot and the screen brightness controls should work however the screen brightness range goes from 0 to 4882 (/sys/class/backlight/intel_backlight/max_brightness) instead of around 100 to 4882 so if you dim the brightness all the way down, your screen will be completely black.