Brightness controls not working on a Sony Vaio VPCEH38FN

I have ubuntu 12.04 installed on windows 7. When I use the Fn alongside the key to reduce brightness, or even using the system settings, I am not being able to reduce the screen brightness. What is the problem?

Solution 1:

Run:

sudo gedit /etc/default/grub

Update these lines:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

... with the following arguments:

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

Then run sudo update-grub and reboot.

Solution 2:

I have a SONY VPCEG Vaio and to manipulate brightness in Ubuntu. Based on a article that I lost, I use this:

https://github.com/ricardodani/sony-vpc-brightness-linux/blob/master/bright.py

Solution 3:

Here's how i fixed mine :

LCD Brightness Control

Once you have installed the proprietary Nvidia drivers as suggested above, you may notice that your brightness control keys do not work properly. This is fixable by editing one's xorg.conf file. Open a terminal window and type the following:

sudo nano /etc/X11/xorg.conf

This will open your X server configuration (after prompting for your password). You should see a section titled "Device" that looks as follows:

Section "Device"
        Identifier      "Default Device"
        Driver  "nvidia"
        Option  "NoLogo"        "True"
EndSection

Append a line so it appears like this:

Section "Device"
        Identifier      "Default Device"
        Driver  "nvidia"
        Option  "NoLogo"        "True"
        Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

You will need to restart your graphical server (or reboot) for this change to take effect.