Ubuntu – 13.04 Upgrade – Brightness not working

13.04brightnessupgrade

Up until yesterday I was running Ubuntu 12.10 on my Dell Latitude E6530. Recently I played around with the nvidia settings, which caused my brightness control to stop working. However, I could fix it by adding Option "RegistryDwords" "EnableBrightnessControl=1" to /etc/X11/xorg.conf as advised in [1].

Now, last night I upgraded to Ubuntu 13.04 because I needed are newer kernel. After that, the brightness control once again stopped working. But this time, [1] doesn't help. I have also tried the methods in [2]:

acpi_backlight=vendor in /etc/default/grub
acpi_osi=Linux in /etc/default/grub
echo $SOME_VALUE | sudo tee /sys/class/backlight/dell_backlight/brightness

None of them are working, the brightness just doesn't change, but that's about all I could find for this problem. Any ideas on how I can get my brightness control back?

[1] https://askubuntu.com/a/270830

[2] https://askubuntu.com/a/289178/213036

Best Answer

I have similar issue with my Sony Vaio. I tried all the methods that you have listed, but there was no effect.

However, in grub, editing lines as follows helped me. (Be sure to backup grub before any editing as a standard practice).

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=legacy" GRUB_CMDLINE_LINUX="acpi_backlight=legacy"

_{Note: We are using acpi_backlight=legacy instead of acpi_backlight=vendor here.}

After saving, run command $ sudo update-grub and reboot your laptop.

Once I did that, the commands cat and tee started working for me to display and change brightness from Terminal.

This will give you maximum numeric value of brightness that your screen supports.
```
$ cat /sys/class/backlight/dell_backlight/max_brightness
```
This will set your screen brightness value to your specified value, between 0 to max_brightness.
```
$ echo <brightness_value> | sudo tee /sys/class/backlight/dell_backlight/brightness
```

For more information, refer to this backlight Wiki.

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Ubuntu – Screen brightness control not working on Lenovo T530

I had a similar problem on my thinkpad W530. I finally found a solution here:

http://blog.pearce.org.nz/2012/08/enabling-external-monitor-on-lenovo.html

These days X automatically configures itself, so you can't just edit the xorg.conf file, you instead need to add a section to a file in /usr/share/X11/xorg.conf.d/ and X will include that section in the configuration that it automatically generates.

So to get the screen brightness keys working with your Nvidia graphics card, create a file in the xorg.conf.d directory, e.g:

sudo gedit /usr/share/X11/xorg.conf.d/10-nvidia-brightness.conf

Paste the following into the file:

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "Quadro K1000M"
    Option         "RegistryDwords" "EnableBrightnessControl=1"
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Ubuntu – Lenovo Y500 can’t set brightness

I installed Xubuntu 12.10 on my new Lenovo Y500 and also could not adjust brightness, it was at at maximum and could not be controlled. Get installed and used graphics driver:

lshw -c video

Gave me:

configuration: drigver=nouveau latency=0

changing the value in /sys/class/backlight/acpi_video0/brightness does not change brightness
booting with acpi_backlight=vendor does not change brightness
etpci -s 00:01.0 F4.B=XX (XX = 00 to ff) does not change brightness

For the moment I solved this by installing the nvidia driver:

sudo apt-get install linux-source
sudo apt-get install linux-headers-generic
sudo apt-get install nvidia-current-updates

This gives you the terminal command:

sudo nvidia-settings

Go to: DFP-0-(LGD), Tab: Color Correction

Here you can set the brightness.

Best Answer

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