No brightness control, HP dv3500 laptop / GeForce GPU

Question

I feel almost stupid asking a brightness question with all the similar ones out there, but I haven't yet found a working solution, so here goes:

System

HP dv3500 series laptop (dv3550eo - Scandinavian version) with a GeForce 9300M GS graphics card, drivers version 280.13 running on Ubuntu 11.10.

The system keys for changing brightness are Fn+F7 and Fn+F8, respectively, but nothing happens - I can't change the brightness.

A few of the tricks I've tried:

• The same tricks this Lenovo owner tried: Unable to change brightness in a Lenovo laptop
• this: http://ubuntuforums.org/showpost.php?p=11543948&postcount=40
• Triedls /sys/class/backlight/acpi_video0/brightness
• also for acpi_video1 and acpi_video2. Nothing was found for any of them.

I'm guessing it's a driver problem, but I've already installed the nvidia drivers (there was a popup upon first restart after install).

I apologize in advance for not reiterating the rest of the suggested fixes I've tried, as they are too numerous for me to remember, and have frankly left me exhausted.

I hope a user with a similar computer to mine has found a fix, elsewise I fear this shall be the fourth time over the years I've given Linux a crack only to give it up again within a fortnight :-/

Fingers crossed for a solution.

Answer 1

Please try smartdimmer. I've succeeded using it via command line, now looking a way to bind it to fn+f7 and fn+f8.

Answer 2

Open /etc/default/grub with your favorite text editor, ie gedit

gksudo gedit /etc/default/grub

Look for the line

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

and add acpi_backlight=vendor to it so that it reads

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Update grub to include the changes done

sudo update-grub

Reboot

sudo reboot