I recently purchased a Lenovo IdeaPad Y450 Laptop, but the screen brightness was not being adjusted when I used the proper key combination (FN+UP/DOWN).  The key combination did show the brightness bar, but did not adjust the actual brightness on the (LED) LCD.  To fix this, edit /etc/default/grub:

Change:

GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash”

to

GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash nomodeset acpi_backlight=vendor”

Then run

sudo update-grub

And restart!

Tags: , , , , , , , , ,