By Iliya Jokic — Apr 24, 2023

Enabling Brightness Control for Nvidia GeForce 9400M on MacBook Pro5,5 with Nvidia driver 340

The NVIDIA GeForce 9400M is an older GPU commonly found in some MacBook models. While it may not support the latest features, it's still possible to enable brightness control using the function keys on your MacBook running Ubuntu. This article will guide you through the process of setting up brightness control on a MacBook with an NVIDIA GeForce 9400M GPU.

Step 1: Install the NVIDIA Proprietary Driver
To get started, you'll need to install the NVIDIA proprietary driver for the GeForce 9400M. Open a terminal and enter the following command:

sudo apt install nvidia-driver-340

Step 2: Open the NVIDIA X Server Settings Application
Once the driver is installed, open the NVIDIA X Server Settings application by running the following command in the terminal:

sudo nvidia-settings

Step 3: Save the X Configuration File
In the NVIDIA X Server Settings application, navigate to "X Server Display Configuration" and click "Save to X Configuration File" at the bottom right. After saving the file, quit the application.

Step 4: Edit the X11 Configuration File
Now, you'll need to edit the X11 configuration file to enable brightness control. Open a terminal and enter the following command:

sudo nano /etc/X11/xorg.conf

Step 5: Modify the "Device" Section**
Locate the "Device" section in the X11 configuration file and add the following line:

Option         "RegistryDwords" "EnableBrightnessControl=1"

The modified "Device" section should look like this:

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce 9400M"
    Option         "RegistryDwords" "EnableBrightnessControl=1"
EndSection

Step 6: Save and Exit the Text Editor
To save your changes, press Ctrl + X, followed by Y and Enter.

Step 7: Restart Your System
Finally, restart your system for the changes to take effect.

After completing these steps, the brightness keys on your MacBook should now be functional. If you still encounter issues with brightness control, you can explore manual methods for adjusting brightness as an alternative.

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