After a fresh install of Julia in an Asus eeePC 1001P, I noticed that the light of the screen was lower than usual. To fix this, do:

1. Open a terminal and run sudo gedit /etc/default/grub
2. Change the line that says
   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
to
   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"
3. Save the file and quit
4. In a terminal run sudo update-grub
5. Reboot

This tutorial by MindBoosterNoori was posted originally at his blog and it's reproduced here with his authorization.