Screen brightness not working

Question

I use Ubuntu 12.04 on my Sony Vaio (VPCCW2HGX). At the first times, brightness control works well, but after the activating additional drivers (nvidia accelerated graphics driver) brightness control doesn't work. I searched this issue on so many Ubuntu and Linux forums, but solutions doesn't work. I tried these ways:

1. Installing xbacklight
2. Adding Option "RegistryDwords" "EnableBrightnessControl=1" to /etc/X11/xorg.conf
3. Updating Nvidia drivers
4. To try to change brightness by typing sudo setpci -s 00:02.0 F4.B=xx

All of these ways doesn't work. I still can't set screen brightness. Is there anyone know this?

Answer 1

To get working brightness keys, try the following.

Run the command:

sudo -H gedit /etc/default/grub

Change this line

GRUB_CMLINE_LINUX_DEFAULT="quiet splash"

to something like below

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor

Execute sudo update-grub and reboot. See if brightness keys are working.

It is still possible Ubuntu won't remember your brightness settings. So you have to change brightness each time.

Please let us know the result as many Sony users are facing this problem.

---

This is for setting brightness manually after doing the above steps.

Try following for paths shown by ls /sys/class/backlight/*/brightness and replace accordingly.

For example, paths will be like:

/sys/class/backlight/acpi_video0/brightness

For the above path Get the maximum brightness:

cat /sys/class/backlight/acpi_video0/max_brightness

Try a lower value to set the brightness, say output is 16 so I will try with half of it:

echo 8 | sudo tee  /sys/class/backlight/acpi_video0/brightness

If this works, make this happen in each login automatically by doing the following

sudo -H gedit /etc/rc.local

Enter this line just before exit 0. It should look like:

echo YOUR_VALUE_HERE > /sys/class/backlight/acpi_video0/brightness
exit 0

Also you can try with xdotool

Answer 2

For those who end up here while looking for a solution, I've found the text below from here and this works for my Ubuntu 12.04 64bit.

sudo nano /etc/X11/xorg.conf

This will open your X server configuration (after prompting for your password). You should see a section titled "Device" that looks as follows:

Section "Device"
        Identifier      "Default Device"
        Driver  "nvidia"
        Option  "NoLogo"        "True"
EndSection

Append a line so it appears like this:

Section "Device"
        Identifier      "Default Device"
        Driver  "nvidia"
        Option  "NoLogo"        "True"
        Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

You will need to restart your graphical server (or reboot) for this change to take effect.

Answer 3

Actually both grub and xorg.conf modifications are needed.

First modify /etc/defaults/grub to add ACPI parameters. The GRUB_CMDLINE_LINUX_DEFAULT line may then look liee:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"

Update GRUB to apply that change, by running the command:

sudo update-grub

Second, in the file /etc/X11/xorg.conf, find the in Device section and add Option EnableBrightnessControl, so it looks like this:

Section "Device"
     Identifier     "Device0"
     Driver         "nvidia" 
     VendorName     "NVIDIA Corporation" 
     BoardName      "GeForce GT 330M" 
     Option         "RegistryDwords" "EnableBrightnessControl=1"
EndSection

This works for me on Samsung R780 with Nvidia GeForce 330M.

Answer 4

I had the same problem with my Vaio and Ubuntu.

I got it working with the nvidiabl-module and the oBacklight script.

The script is available from this repository, and these instructions may be helpful.

Or use the newer DKMS-based way described in the README file. If you use that technique, you really should read that file thoroughly. However, one method that should work is to download a .deb file and install it. The project is inactive so nvidiabl-dkms_0.87_all.deb will likely remain the latest .debpackage. You can download and install that package with these two commands:

wget https://raw.githubusercontent.com/guillaumezin/nvidiabl/master/install/deb/nvidiabl-dkms_0.87_all.deb
sudo dpkg -i nvidiabl-dkms_0.87_all.deb

The README has information on other ways to install, as well as uninstalling.

Answer 5

Install xbacklight:

sudo apt-get install xbacklight

You can set brightness to X% as (no sudo required):

xbacklight -set X

To make the setting permanent, go to Startup Applications and add a new startup program, with the following command (where X% is your desired brightness):

xbacklight -set X

Modifying /etc/rc.local as many others have suggested does not work for me (on a Dell Studio 1535).

Answer 6

I use nvidia 970. I wrote a script and mapped keyboard shortcuts to increase or decrease brightness ( This uses xrandr ):

Remember to give executed permission to file

chmod +xfile

Add the following line to keyboard shortcuts

To increase:

filepath/file--increment

and to decrease

filepath/file--decrement

where file is the name of file containing the below script:

#!/bin/sh

#get the video port to which screen is connected

VAR_DISPLAY=`xrandr --verbose | grep  " connected"| sed 's/ connected.*//g'`

if [ -z $VAR_DISPLAY ]

then

        echo "Err:Display details could not be found using xrandr"
        exit 1
fi

echo $VAR_DISPLAY

##

#get the current brightness settings [0 - 1]

VAR_BRIGHTNESS=$(xrandr --verbose | grep  "Brightness"| sed 's/.*Brightness: //g')

if [ -z $VAR_BRIGHTNESS ]

then

        echo "Err:Brightness setting could not be found using xrandr"
        exit 1
fi

##

#increase or decrease brightness

if [ -z $1 ]

then

        echo "Specify one of following option --increment | --decrement"
else if [ $1 = "--increment" ]

then

        test $( expr `expr "$VAR_BRIGHTNESS + .05"|bc`" > 1"|bc ) -eq 1 || xrandr --output $VAR_DISPLAY --brightness `expr "$VAR_BRIGHTNESS +.05"|bc`
else if [ $1 = "--decrement" ]

then

        test $( expr `expr "$VAR_BRIGHTNESS - .05"|bc`" < 0"|bc ) -eq 1 || xrandr --output $VAR_DISPLAY --brightness `expr "$VAR_BRIGHTNESS - .05"|bc`
else

        echo "Specify one of following option --increment | --decrement"
fi

fi

fi

##

Answer 7

I have a fix for my sony vaio F Model # VPCF23EFX by Follow the steps below:

1. install Nvidia drive

2. run Nidia x server settings which you can find in appliction menu

3. select x server display configuration and chose the save to x configuration file option. This will build file xorg.conf and close Nvidia x server settings.

4. sudo gedit /etc/X11/xorg.conf in terminal

5. find

   Section "Device"
   Identifier     "Device0"
   Driver         "nvidia"
   VendorName     "NVIDIA Corporation"
   BoardName      "GeForce GT 540M"
   EndSection 
   

6. change it like this

   Section "Device"
   Identifier     "Device0"
   Driver         "nvidia"
   VendorName     "NVIDIA Corporation"
   BoardName      "GeForce GT 540M"
   Option "RegistryDwords" "EnableBrightnessControl=1"
   EndSection
   

7. reboot

Answer 8

I also had a problem using xbacklight to control display brightness while using the nvidia driver.

I found that using light was the best generic solution, as it doesn't rely on xorg configuration.

Here are the changes I made to my dotfiles in order to install and use it with keyboard shortcuts: https://github.com/ruebenramirez/.dotfiles/commit/a18fd396a4f53238c7d6d96e3e0d39bdbae2c56c

Answer 9

Try using xrandr to change the brightness or gamma while using the nvdidia drivers:

determine the output name of your monitor:

xrandr -q | grep connected

my monitor name is returned as DVI-I-1 and I use:

xrandr --output DVI-I-1 --brightness 0.8 --gamma 0.7:0.7:0.7

to change the brightness/gamma

You can create custom keys that run these commands.