can't control the brightness on Ubuntu 13.10

Question

I have Ubuntu 13.10 in my dell inspiron 3521 with Intel core i5 and graphics of Intel Ivibridge Mobile. I can adjust the brightness of the screen. All the solutions that I found was to try to change the grub file as suggested in How do I get the brightness control working on a Lenovo Yoga 13? BUT I get my screen stop running when the screen get dimmed. BTW I have 2 lines in my grub file :

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

I tried to change each one of them (and both) with no luck. Any suggestions ?

Answer 1

Found the solution that worked for me - hope it will help to anyone else: adding "acpi_backlight=vendor" to the grub file isn't enough. you need to add acpi_osi=Linux as well ! I update the grub file in /etc/default/grub :

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"
GRUB_CMDLINE_LINUX=""

than run the next command line from terminal :

sudo update-grub

and than restart.