Adjusting brightness on Dell Vostro 3500 won't work

Question

On a fresh install of Ubuntu 11.04, running Unity, I can't adjust the brightness via Fn+Up/Down. The brightness panel will show, and increase/decrease accordingly, but the actual brightness never changes.

This is an issue I also had on 10.04. I used to fix this by adding this line

Option "RegistryDwords" "EnableBrightnessControl=1"

to my /etc/Xorg/xorg.conf in Section "Device". However it seems this is not working anymore. I also noticed the config file is much smaller that what I remember. Here is the whole file:

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

Should I use this line somewhere else ? or is there something else to fix ?

For reference, here is the original issue on 10.04: https://answers.launchpad.net/ubuntu/+source/xserver-xorg-video-nv/+question/109012

Answer 1

i have same problem on dell vostro 3500 and solution from this question helped me to fix brightness bug: Screen brightness not changing on Acer 5742 notebook

The complete solution is:

1. edit /etc/Xorg/xorg.conf to add the following line in Section "Device":

   Option "RegistryDwords" "EnableBrightnessControl=1"
   

2. edit /etc/default/grub to change the line into:

   GRUB_CMDLINE_LINUX="acpi_osi=Linux"
   

3. run the command:

   sudo update-grub
   

4. reboot

Answer 2

I believe you need to install Nvidia blacklight driver (nvidia-bl-dkms). The package itself has been developed for MacBooks, but they use same Nvidia model – G310M.