Brightness – Fixing Brightness Problem on Samsung 530U3B

You didn't specify which graphics card drivers are you using. With your graphics card it can be either the open source ones, embedded into the kernel, or the proprietay ones that come with the Catalyst management software.

If you are using the proprietary ones, I suggest you try and uninstall them; then you can test wether it was their fault or not.

If you didn't install the Catalyst suite, you can download it here to make the reverse test.

Tell us how it went. :-)

(The situation seems to change with each few new kernel versions, which is very unfortunate.)

After some more experimentation and then fortunately running into this post http://ubuntuforums.org/showpost.php?p=12126780&postcount=6 I have it working on my setup.

You need this in your /etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="nosplash acpi_osi=Linux acpi_backlight=vendor"

After making the changes, do:

sudo update-grub

If you are running the latest Ubuntu 12.04.3 with kernel 3.8.0 (tested on 2013-10-29), or if the above alone does not work after a reboot, you also want to blacklist the samsung_laptop kernel module. Do this by creating a new file in /etc/modprobe.d/ called blacklist-np300.conf with the following contents:

blacklist samsung_laptop

... and then reboot.

I have full backlight control and range restored! If you're wondering what exactly the acpi_osi parameter does, see this askubuntu entry: What does the kernel boot parameter "set acpi_osi=Linux" do?