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Old 04-28-10, 02:54 PM   #48
Creator of oBacklight
Join Date: Apr 2010
Posts: 19
Default Re: Linux backlight driver

Originally Posted by damdim View Post
Here are the steps summarized for the people asking:

1. Install dkms. f.e. in Ubuntu run
sudo apt-get update && sudo apt-get install dkms
2. Download "nvidia_bl-0.52.tar.gz", created by guillaumezin, from the first post of the thread and run the following command in the folder you've saved it.
sudo dkms ldtarball --archive=nvidia_bl-0.52.tar.gz
3. Go to and find your card and note the Device PCI ID f.e. GeForce GT 230M has Device PCI ID "0x0A2A"

4. Edit as root the file "/usr/src/nvidia_bl-0.52/nvidia_bl.c" and in the section "static DEFINE_PCI_DEVICE_TABLE(nvidia_bl_device_table)" add the corresponding line for your card f.e. for GeForce GT 230M the following line has to be added.
/* NVIDIA Geforce 230M */
	{ PCI_VDEVICE(NVIDIA, 0x0A2A), (kernel_ulong_t)&nv5x_driver_data },
5. Save the file and run
sudo dkms add build install -m nvidia_bl -v 0.52
6. Run
sudo modprobe nvidia_bl
to load the module. It should not complain that it didn't find a supported chip.

7. Run
cat /sys/class/backlight/nvidia_backlight/brightness
It should return a number that is your current brightness.

8. Run
echo 50 | sudo tee -a /sys/class/backlight/nvidia_backlight/brightness
It should darken your screen.

9. Edit as root the file "/etc/modules" and add the line "nvidia_bl" so that the module is loaded every time you boot.

10. If you use KDE4 then with the Powerdevil applet you should be able to control the brightness.
If not make sure that you sony-laptop module is loaded. Run
lsmod | grep sony
and if it doesn't return "sony-laptop" run
sudo modprobe sony-laptop
and follow the steps from keptile's post to control the brightness with Fn keys.

I tried the above on my openSUSE 11.2 install and it almost works. the thing not working for me right now is the brightness levels.

When running
cat /sys/class/backlight/nvidia_backlight/brightness
it returns 3324213

When running
echo 50 | sudo tee -a /sys/class/backlight/nvidia_backlight/brightness
The display gets extremly dark and if i try to restore original value is says invalid and i can at most put in 127 which is extremely low on my display.

Tried the scripts from here: with no luck.

Any tips to go that final stretch to get proper backlight control.
muddenhed is offline   Reply With Quote