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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?

Thanks.

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open a terminal and post result of ls /sys/class/*/brightness –  Web-E Jul 11 '12 at 9:46
    
there is nothing in the /sys/class/backlight so i didn't find the path that you say –  sundowatch Jul 11 '12 at 9:53
    
sorry my mistake, Please see the answer –  Web-E Jul 11 '12 at 9:56
    
this method will work on most nvidia devices.. askubuntu.com/a/179050/82136 –  Amir Reza Adib Sep 26 '12 at 15:34
    
this method will work on most nvidia devices.. askubuntu.com/a/179050/82136 –  Amir Reza Adib Sep 26 '12 at 15:35
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6 Answers 6

up vote 4 down vote accepted

I had the same problem with my vaio and ubuntu

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

http://dev.osource.se/docs/obacklight/

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it really works, thanks. Eventually, I couldn't imagine it is solved by a script. I think sony hates Linux :) –  sundowatch Jul 11 '12 at 12:48
1  
not sony but nvidia :) nothing works out of the box backlight, hibernate/suspend, dual-screen,.. –  Achim A Jul 11 '12 at 12:51
    
oh, dual-screen not working? I am falling disappointment. –  sundowatch Jul 11 '12 at 13:50
    
it works, but not everything, e.g. for switching the primary monitor you need to enable/disable/reenable the configuration, etc :) –  Achim A Jul 13 '12 at 9:21
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To get working brightness key. try following

execute sudo 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.

example paths will be like

/sys/class/backlight/acpi_video0/brightness
  1. 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 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 Install xdotool

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I did whatever you say, but still not working. And there is no path like sys/class/backlight/acpi_video0/brightness or sys/class/backlight/acpi_video0/max_brightness. sys/class/backlight/ is empty. My Fn keys works except of brightness keys. –  sundowatch Jul 11 '12 at 10:18
    
did you update the grub with acpi_backlight= vendor ? –  Web-E Jul 11 '12 at 10:49
    
yes, i updated the grub, and still not working –  sundowatch Jul 11 '12 at 12:15
    
I think it is not about Ubuntu, because I have the same problem on Linux Mint 12. –  sundowatch Jul 11 '12 at 12:20
    
Updating the grub worked for me with Ubuntu 12.10 –  Indika Oct 25 '12 at 17:14
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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).

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Worked for me on my Idepad Y500. GPU Geforce GT 750m. Using ElementaryOS(based on Ubuntu 12.04) –  iamcreasy Mar 3 at 5:29
    
Worked for me on Lenovo W530 with Debian wheezy –  Carlos López-Camey Jul 1 at 1:32
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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.

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Changing screen brightness no longer worked for me on Ubuntu 13.10 after installing nvidia driver. This answer fixed the problem for me. –  brady Mar 24 at 21:18
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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

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Actually both grub and xorg.conf mods are needed

So to summarize:

first mod /etc/defaults/grub add acpi parameters

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

Second /etc/X11/xorg.conf in device section add Option EnableBrightness control.

Section "Device"

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

EndSection

Works for me on Samsung R780 with Nvidia GeForce 330M

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