Krdytkyu

I was able to get my brightness keys working on my Lenovo W530 on Ubuntu 12.04.

These days X automatically configures itself, so creating an xorg.conf file might make your system inflexible. Instead you can 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"

EndSection

Log out and log back in, or reboot, and your brightness keys should now work!

(I blogged this here)

I had a similar issue with my laptop, there is an option you need to add to your /etc/X11/xorg.conf

1. 
   

   Run command:

   
   
   

   sudo nano /etc/X11/xorg.conf
   
   

   
   


2. 
   

   Find the line Section "Device" and add the following

   
   
   

   Option "RegistryDwords" "EnableBrightnessControl=1"    
   
   

   
   

You need to enable Brightness Control.
Open terminal and type sudo gedit /etc/x11/xorg.conf
And then add Option "RegistryDwords" "EnableBrightnessControl=1" inside the device section, paste it in a new line.
Then restart your computer and everything should be fine.

Thank you for providing the great script qgj. It's sad that this bug still persists and the work-around is needed. I had the same issue as James getting an error due to the options no longer being valid with nvidia-settings for my specific display type. As luck would have it, there is a better setting available for backlight brightness. I have modified the bash script to use this setting instead.

#!/bin/bash



# This script was originally created by 'qgj' from askubuntu.  It has been modified

# to work using the BacklightBrighness setting available for some displays on the currrent nvidia driver

# It has also been modified to remove display specific configuration, instead applying the setting to all 

# active displays which support the BacklightBrightness setting.

# Tested only with nvidia-settings-319.12 and nvidia-drivers-331.20 on Linux Mint 17 Mate

#

# Requirements:

# - NVIDIA Drivers (e.g. nvidia-current in Ubuntu)

# - NVIDIA Settings (nvidia-settings in Ubuntu)

#

# This script can be used to change the brightness on systems with an NVIDIA graphics card

# that lack the support for changing the brightness (probably needing acpi backlight).

# It uses "nvidia-settings -a" to assign new gamma or brightness values to the display.

# 

# If this script fails, your display likely does not support the 'BacklightBrightness' option.

# In that event, execute 'nvidia-settings -n -q all' to see which options are available for the displays

#

# "nvidia-brightness.sh" may be run from the command line or can be assigned to the brightness keys on your Keyboard

# Type "nvidia-brightness.sh --help" for valid options.



if [ -z "${BASH}" ] ; then

    echo "please run this script with the BASH shell" 

    exit 1

fi



usage ()

{

cat << ENDMSG

Usage: 

   nvidia-brightness.sh [ options ]



Options:

   [ -bu ] or [ --brightness-up ]    increase brightness by 10

   [ -bu <no> ] or                   

   [ --brightness-up <no> ]          increase brightness by specified <no>



   [ -bd ] or [ --brightness-down ]  decrease brightness by 10

   [ -bd <no> ] or                   

   [ --brightness-down <no> ]        decrease brightness by specified <no>



   [ -i ]  or [ --initialize ]       Must be run once to create the settings file

                                     (~/.nvidia-brightness.cfg).

                                     Brightness settings from ~/.nvidia-settings-rc

                                     will be used if file exists, otherwise 

                                     brightness will be set to 100.

   [ -l ]  or [ --load-config ]      Load current settings from ~/.nvidia-brightness.cfg

                                     (e.g. as X11 autostart script)



Examples:

   nvidia-brightness -bd       this will decrease gamma by 10

   nvidia-brightness -bu 15    this will increase brightness by 15

ENDMSG

}



case $1 in 

    -h|--help)

        usage

        exit 0

esac



if [ "$1" != "-i" -a "$1" != "--initialize" ] ; then

    if [[ ! -f ~/.nvidia-brightness.cfg ]]; then 

        echo 'You must run this script with the --initialize option once to create the settings file.'

        echo 'Type "nvidia-brightness.sh --help" for more information.';

        exit 1

    fi

fi



#### INITIALIZE ####

initialize_cfg ()

{

    BRIGHTNESS_TEMP=100

    echo "BRIGHTNESS=$BRIGHTNESS_TEMP" > ~/.nvidia-brightness.cfg



    source ~/.nvidia-brightness.cfg

    echo "BRIGHTNESS: $BRIGHTNESS"



    # Valid BacklightBrightness values are between 0 and 100

    # Example:  nvidia-settings -n -a BacklightBrightness=80

    nvidia-settings -n -a BacklightBrightness=$BRIGHTNESS 1>/dev/null

    exit $?

}



#### LOAD CONFIGURATION ####

load_cfg ()

{

    source ~/.nvidia-brightness.cfg

    echo "BRIGHTNESS: $BRIGHTNESS"



    nvidia-settings -n -a BacklightBrightness=$BRIGHTNESS 1>/dev/null

}



#### BRIGHTNESS CHANGE ####

brightness_up ()

{

    source ~/.nvidia-brightness.cfg



    [[ -z $1 ]] && BRIGHTNESS_INC=10 || BRIGHTNESS_INC=$1

    BRIGHTNESSNEW=$(( $BRIGHTNESS + $BRIGHTNESS_INC ))

    [[ $BRIGHTNESSNEW -gt 100 ]] && BRIGHTNESSNEW=100



    sed -i  s/.*BRIGHTNESS=.*/BRIGHTNESS=$BRIGHTNESSNEW/g ~/.nvidia-brightness.cfg



    source ~/.nvidia-brightness.cfg

    echo "BRIGHTNESS: $BRIGHTNESS"



    nvidia-settings -n -a BacklightBrightness=$BRIGHTNESS 1>/dev/null

}



brightness_down ()

{

    source ~/.nvidia-brightness.cfg



    [[ -z $1 ]] && BRIGHTNESS_INC=10 || BRIGHTNESS_INC=$1

    BRIGHTNESSNEW=$(( $BRIGHTNESS - $BRIGHTNESS_INC ))

    [[ $BRIGHTNESSNEW -lt 0 ]] && BRIGHTNESSNEW=0



    sed -i  s/.*BRIGHTNESS=.*/BRIGHTNESS=$BRIGHTNESSNEW/g ~/.nvidia-brightness.cfg



    source ~/.nvidia-brightness.cfg

    echo "BRIGHTNESS: $BRIGHTNESS"



    nvidia-settings -n -a BacklightBrightness=$BRIGHTNESS 1>/dev/null

}



if [[ "$3" != "" ]]; then

    usage

    exit 1

fi



error_mixed_brightness ()

{

    echo "Error: [ --brightness-up ] and [ --brightness-down ] can't be used together."

}



if [[ "$2" != "" ]]; then

    [[ ! "$2" == ?(-)+([0-9]) ]] && usage && exit 1

fi



case $1 in

    -bu|--brightness-up) 

        [ "$2" == "-bd" ] && error_mixed_brightness && exit 1

        [ "$2" == "--brightness-down" ] && error_mixed_brightness && exit 1

        brightness_up $2

        ;;

    -bd|--brightness-down) 

        [ "$2" == "-bu" ] && error_mixed_brightness && exit 1

        [ "$2" == "--brightness-up" ] && error_mixed_brightness && exit 1

        brightness_down $2

        ;;

    -h|--help) 

        usage

        exit 0

        ;;

    -i|--initialize)

        if [ "$2" != "" ]; then usage; exit 1; fi   

        initialize_cfg

        exit $?

        ;;

    -l|--load-config)

        if [ "$2" != "" ]; then usage; exit 1; fi   

        load_cfg

        exit 0

        ;;

    *) 

        usage

        exit 1

esac

Your mileage may vary with this script as some displays/adapters support different options. If you encounter issues with it please read the help and comments in the script.

Hope it helps someone!

There are some computers, such as my Lenovo W520, that don't with the Option "RegistryDwords" "EnableBrightnessControl=1" line. If you are one of those unlucky ones, you can try the nvidiabl driver (link here).

The nvidiabl driver provides a proper way to change the screen brightness. On some laptops the Option "RegistryDwords" "EnableBrightnessControl=1" hack will cause the backlight controller or your GPU to emit a high pitched noise.

Just download and install the latest Deb file from here: https://github.com/downloads/guillaumezin/nvidiabl/nvidiabl-dkms_0.72_all.deb

and run:

echo "nvidiabl" | sudo tee -a /etc/modules

to ensure that the module will be loaded when the computer boots.

Im personally using Vaio VPCCW21FX (Nvidia Graphic) and Ubuntu Studio 11.10 ..
I tried many solutions and nothing could resolve my problem with LCD brightness!
Finally wrote these two perl files to manually set brightness/Contrast and Gamma functions inside Nvidia driver config file.

This will be helpfull only if you are able to change brightness within Nvidia X Server Settings

Step 1: create this file and name it "Brightness-Up.pl"
(you can use any text editing tool like : gedit,nano,vi,etc.. copy & paste)

    ### Code by forgottenrip@yahoo.com ###

    my $find1 = "0/RedBrightness=";my $find2 = "0/RedGamma=";

open FILE, "<Nvidia-Settings.cfg";

my @lines = <FILE>;

for (@lines) {

    if ($_ =~ /$find1/) { chomp $_;$value= substr($_,16,5); }

    if ($_ =~ /$find2/) { chomp $_;$value2= substr($_,11,5);}     

}

my @Lines;

if ( $value > 0.0) { $value = $value - 0.30 };  

if ( $value2 > 1.1) { $value2 = $value2 - 0.08 };  

$last_value = $value + 0.30;

$Lines[0] ="0/RedBrightness=".$last_value;

$Lines[1] ="0/GreenBrightness=".$last_value;;

$Lines[2] ="0/BlueBrightness=".$last_value;;

$last_value = $value + 0.30;

$Lines[3] ="0/RedContrast=".$last_value;;

$Lines[4] ="0/GreenContrast=".$last_value;;

$Lines[5] ="0/BlueContrast=".$last_value;;

$last_value = $value2 + 0.08;

$Lines[6] ="0/RedGamma=".$last_value;;

$Lines[7] ="0/GreenGamma=".$last_value;;

$Lines[8] ="0/BlueGamma=".$last_value;;



$filename = "Nvidia-Settings.cfg";

open fh2,'>',$filename or die ("can't open '$filename': $! n");

foreach ( @Lines )

{ chomp;print "$_n";print fh2 "$_n"; };

close fh2; 

`nvidia-settings -l --config=Nvidia-Settings.cfg`;

Step 2: then make another file, name it "Brightness-Down.pl" and fill with this code:

    ### Code by forgottenrip@yahoo.com ###

    my $find1 = "0/RedBrightness=";my $find2 = "0/RedGamma=";

open FILE, "<Nvidia-Settings.cfg";

my @lines = <FILE>;

for (@lines) {

    if ($_ =~ /$find1/) {chomp $_;$value= substr($_,16,5);}

    if ($_ =~ /$find2/) {chomp $_;$value2= substr($_,11,5);}     

}

my @Lines;

if ( $value < -0.80) { $value = $value + 0.30 };  

if ( $value2 < 0.8) { $value2 = $value2 + 0.08 };  

$last_value = $value - 0.30;

$Lines[0] ="0/RedBrightness=".$last_value;

$Lines[1] ="0/GreenBrightness=".$last_value;;

$Lines[2] ="0/BlueBrightness=".$last_value;;

$last_value = $value - 0.30;

$Lines[3] ="0/RedContrast=".$last_value;;

$Lines[4] ="0/GreenContrast=".$last_value;;

$Lines[5] ="0/BlueContrast=".$last_value;;

$last_value = $value2 - 0.08;

$Lines[6] ="0/RedGamma=".$last_value;;

$Lines[7] ="0/GreenGamma=".$last_value;;

$Lines[8] ="0/BlueGamma=".$last_value;;



$filename = "Nvidia-Settings.cfg";

open fh2,'>',$filename or die ("can't open '$filename': $! n");

foreach ( @Lines )

{ chomp;print "$_n";print fh2 "$_n"; };

close fh2; 

`nvidia-settings -l --config=Nvidia-Settings.cfg`;

Step 3: You need to create another file which contains Nvidia Settings..
name it "Nvidia-Settings.cfg" its important that you write name exactly same.
fill with:

0/RedBrightness=0.1

0/GreenBrightness=0.1

0/BlueBrightness=0.1

0/RedContrast=0.1

0/GreenContrast=0.1

0/BlueContrast=0.1

0/RedGamma=1.14

0/GreenGamma=1.14

0/BlueGamma=1.14

Thats it! now place these files in unique folder.. you have to bind your Function Keys to these two perl file.you can use Compiz>commands to do that.
Run below command to install the compizconfig-settings-manager

sudo apt-get install compizconfig-settings-manager

or even you can run seperately with these two commands in shell (terminal):

user$ perl Brightness/Brightness-Up.pl

user$ perl Brightness/Brightness-Down.pl

where Brightness is folder I put those files in it.

The other answers are good steps to try, but note that some combinations of Ubuntu/Linux Kernel and the Nvidia driver just won't work. I used 12.04 for years, and even though I tried all the above answers, I couldn't get any of the Nvidia drivers to support screen dimming on my Macbook Pro 5,5.

When I finally upgraded to 14.04, I tried the Nouveau driver, which did support screen dimming, and was generally faster and more reliable and Nvidia. Unfortunately, it doesn't support suspend/resume, making it useless on a laptop. I switched back to Nvidia, but several drivers caused X/lightdm to crash, preventing me from even logging in. I finally found that the Nvidia 340 driver was stable with my Macbook Pro 5,5 and Ubuntu 14.04 and also supported dimming.

FYI, just worked through this on a Lenovo W520, and the addition of the simple line
Option "RegistryDwords" "EnableBrightnessControl=1"

to xorg.conf was enough - no need for any of the other bogosity, and all works fine with a current NVidia release (specifically, running 346.35)

NVIDIA brightness bash script

The above perl script didnt work for me so I wrote my own script as a bash script (since I don't know perl). It got a bit long but it creates the settings file by itself and can be used with command line options to adjust brightness or gamma or both at the same time.
I use it with the --brightness-up and --brightness-down switches for the brightness keys on my Keyboard. Easy to assign in XFCE4 and surely also in KDE / GNOME.

nvidia-brightness.sh:

#!/bin/sh



# Tested only with nvidia-settings-319.12 and nvidia-drivers-319.17 on Funtoo Linux running XFCE 4.10

#

# Requirements:

# - NVIDIA Drivers (e.g. nvidia-current in Ubuntu)

# - NVIDIA Settings (nvidia-settings in Ubuntu)

# - xrandr (used by default to determine the correct display name)

#

# This script can be used to change the brightness on systems with an NVIDIA graphics card

# that lack the support for changing the brightness (probably needing acpi backlight).

# It uses "nvidia-settings -a" to assign new gamma or brightness values to the display.

#

# "nvidia-brightness.sh" may be run from the command line or can be assigned to the brightness keys on your Keyboard

# e.g. in XFCE4.

#

# Type "nvidia-brightness.sh --help" for valid options.



usage ()

{

cat << ENDMSG

Usage: 

   nvidia-brightness.sh [ options ]

Options:

   [ -gu ] or [ --gamma-up ]         increase gamma by 0.1

   [ -gd ] or [ --gamma-down ]       decrease gamma by 0.1

   [ -bu ] or [ --brightness-up ]    increase brightness by 0.1

   [ -bd ] or [ --brightness-down ]  decrease brightness by 0.1

   [ -i ]  or [ --initialize ]       Must be run once to create the settings file

                                     (~/.nvidia-brightness.cfg).

                                     Brightness settings from ~/.nvidia-settings-rc

                                     will be used if file exists, otherwise 

                                     gamma will be set to 1.0 and brightness to 0.0

                                     (NVIDIA Standard).

   [ -l ]  or [ --load-config ]      Load current settings from ~/.nvidia-brightness.cfg

                                     (e.g. as X11 autostart script)



Examples:

   nvidia-brightness -gd       this will decrease gamma by 0.1

   nvidia-brightness -bu -gd   this will increase brightness by 0.1 and decrease gamma by 0.1

ENDMSG

}



case $1 in 

    -h|--help)

        usage

        exit 0

esac



if [ "$1" != "-i" -a "$1" != "--initialize" ]; then

    if [ ! -f ~/.nvidia-brightness.cfg ]; then 

        echo 'You must run this script with the --initialize option once to create the settings file.'

        echo 'Type "nvidia-brightness.sh --help" for more information.';

        exit 1

    fi

fi



#### INITIALIZE ####

initialize_cfg ()

{

CONNECTED="[`xrandr | grep " connected" | awk '{ print $1 }'`]"

#CONNECTED="`cat ~/.nvidia-settings-rc  | grep RedBrightness | grep -o "[.*]"`"

#CONNECTED="[DVI-I-1]"

#CONNECTED="[dpy:2]"

#CONNECTED="0"



if [ -f ~/.nvidia-settings-rc ]; then 

    if [ "`grep RedGamma ~/.nvidia-settings-rc`" != "" ]; then

        if [ "`grep RedBrightness ~/.nvidia-settings-rc`" != "" ]; then

            GAMMA_TEMP=`grep RedGamma= ~/.nvidia-settings-rc | sed s/^.*=//`

            BRIGHTNESS_TEMP=`grep RedBrightness= ~/.nvidia-settings-rc | sed s/^.*=//`

            NVIDIA_SETTINGS_OK=1

        fi

    fi

fi





[ "$NVIDIA_SETTINGS_OK" != "1" ] && 

GAMMA_TEMP=1.000000 

BRIGHTNESS_TEMP=0.000000



echo "

CONNECTED_DISPLAY=$CONNECTED

GAMMA=$GAMMA_TEMP

BRIGHTNESS=$BRIGHTNESS_TEMP" > ~/.nvidia-brightness.cfg



source ~/.nvidia-brightness.cfg



GAMMACOMMA=`echo $GAMMA | sed s/"."/","/`

BRIGHTNESSCOMMA=`echo $BRIGHTNESS | sed s/"."/","/`



nvidia-settings -n -a $CONNECTED_DISPLAY/Gamma=$GAMMACOMMA -a $CONNECTED_DISPLAY/Brightness=$BRIGHTNESSCOMMA 1>/dev/null

}



#### LOAD CONFIGURATION ####

load_cfg ()

{

source ~/.nvidia-brightness.cfg



GAMMACOMMA=`echo $GAMMA | sed s/"."/","/`

BRIGHTNESSCOMMA=`echo $BRIGHTNESS | sed s/"."/","/`



nvidia-settings -n -a $CONNECTED_DISPLAY/Gamma=$GAMMACOMMA -a $CONNECTED_DISPLAY/Brightness=$BRIGHTNESSCOMMA 1>/dev/null

}



#### GAMMA CHANGE ####

gamma_up ()

{

source ~/.nvidia-brightness.cfg



GAMMANEW=`echo $GAMMA | awk '{printf "%f", $GAMMA + 0.100000}'`



GAMMACOMMA=`echo $GAMMANEW | sed s/"."/","/`



nvidia-settings -n -a $CONNECTED_DISPLAY/Gamma=$GAMMACOMMA  1>/dev/null 



sed -i  s/.*GAMMA=.*/GAMMA=$GAMMANEW/g ~/.nvidia-brightness.cfg

}



gamma_down ()

{

source ~/.nvidia-brightness.cfg



GAMMANEW=`echo $GAMMA | awk '{printf "%f", $GAMMA - 0.100000}'`



GAMMACOMMA=`echo $GAMMANEW | sed s/"."/","/`



nvidia-settings -n -a $CONNECTED_DISPLAY/Gamma=$GAMMACOMMA  1>/dev/null



sed -i  s/.*GAMMA=.*/GAMMA=$GAMMANEW/g ~/.nvidia-brightness.cfg

}



#### BRIGHTNESS CHANGE ####

brightness_up ()

{

source ~/.nvidia-brightness.cfg



BRIGHTNESSNEW=`echo $BRIGHTNESS | awk '{printf "%f", $BRIGHTNESS + 0.100000}'`



BRIGHTNESSCOMMA=`echo $BRIGHTNESSNEW | sed s/"."/","/`



nvidia-settings -n -a $CONNECTED_DISPLAY/Brightness=$BRIGHTNESSCOMMA 1>/dev/null



sed -i  s/.*BRIGHTNESS=.*/BRIGHTNESS=$BRIGHTNESSNEW/g ~/.nvidia-brightness.cfg

}



brightness_down ()

{

source ~/.nvidia-brightness.cfg



BRIGHTNESSNEW=`echo $BRIGHTNESS | awk '{printf "%f", $BRIGHTNESS - 0.100000}'`



BRIGHTNESSCOMMA=`echo $BRIGHTNESSNEW | sed s/"."/","/`



nvidia-settings -n -a $CONNECTED_DISPLAY/Brightness=$BRIGHTNESSCOMMA 1>/dev/null



sed -i  s/.*BRIGHTNESS=.*/BRIGHTNESS=$BRIGHTNESSNEW/g ~/.nvidia-brightness.cfg

}



if [ "$3" != "" ]; then

    usage

    exit 1

fi



error_mixed_gamma ()

{

    echo "Error: [ --gamma-up ] and [ --gamma-down ] can't be used together."

}



error_mixed_brightness ()

{

    echo "Error: [ --brightness-up ] and [ --brightness-down ] can't be used together."

}





if [ "$2" != "" ]; then

    [ "$2" != "-bu" -a "$2" != "--brightness-up" -a "$2" != "-bd" -a "$2" != "--brightness-down" 

    -a "$2" != "-gu" -a "$2" != "--gamma-up" -a "$2" != "-gd" -a "$2" != "--gamma-down" ] && usage && exit 1

fi



case $1 in

    -gu|--gamma-up) 

        [ "$2" == "-gd" ] && error_mixed_gamma && exit 1

        [ "$2" == "--gamma-down" ] && error_mixed_gamma && exit 1

        gamma_up

        ;;

    -gd|--gamma-down) 

        [ "$2" == "-gu" ] && error_mixed_gamma && exit 1

        [ "$2" == "--gamma-up" ] && error_mixed_gamma && exit 1

        gamma_down

        ;;

    -bu|--brightness-up) 

        [ "$2" == "-bd" ] && error_mixed_brightness && exit 1

        [ "$2" == "--brightness-down" ] && error_mixed_brightness && exit 1

        brightness_up

        ;;

    -bd|--brightness-down) 

        [ "$2" == "-bu" ] && error_mixed_brightness && exit 1

        [ "$2" == "--brightness-up" ] && error_mixed_brightness && exit 1

        brightness_down

        ;;

    -h|--help) 

        usage

        exit 0

        ;;

    -i|--initialize)

        if [ "$2" != "" ]; then usage; exit 1; fi   

        initialize_cfg

        exit 0

        ;;

    -l|--load-config)

        if [ "$2" != "" ]; then usage; exit 1; fi   

        load_cfg

        exit 0

        ;;

    *) 

        usage

        exit 1

esac



case $2 in

    -gu|--gamma-up) 

        gamma_up

        ;;

    -gd|--gamma-down) 

        gamma_down

        ;;

    -bu|--brightness-up) 

        brightness_up

        ;;

    -bd|--brightness-down) 

        brightness_down

        ;;

    -h|--help) 

        usage

        exit 0

        ;;

    "")

        ;;

    *) 

        usage

        exit 1

esac

Usage:

Save the file somewhere in your PATH e.g.

/usr/local/bin/nvidia-brightness.sh

Don't forget to

chmod +x /usr/local/bin/nvidia-brightness.sh

Before you can use it you have to type

nvidia-brightness.sh -i

This will create the settings file and can also be used to reset the brightness at any time.

Type

nvidia-settings.sh --help

for more options:

Usage: 

   nvidia-brightness.sh [ options ]

Options:

   [ -gu ] or [ --gamma-up ]         increase gamma by 0.1

   [ -gd ] or [ --gamma-down ]       decrease gamma by 0.1

   [ -bu ] or [ --brightness-up ]    increase brightness by 0.1

   [ -bd ] or [ --brightness-down ]  decrease brightness by 0.1

   [ -i ]  or [ --initialize ]       Must be run once to create the settings file

                                     (~/.nvidia-brightness.cfg).

                                     Brightness settings from ~/.nvidia-settings-rc

                                     will be used if file exists, otherwise 

                                     gamma will be set to 1.0 and brightness to 0.0

                                     (NVIDIA Standard).

   [ -l ]  or [ --load-config ]      Load current settings from ~/.nvidia-brightness.cfg

                                     (e.g. as X11 autostart script)



Examples:

   nvidia-brightness -gd       this will decrease gamma by 0.1

   nvidia-brightness -bu -gd   this will increase brightness by 0.1 and decrease gamma by 0.1

Im using NVIDIA Graphic Card and having problem like you.
But i tried this thing and it's work :


1. Install NVIDIA Driver with command :

sudo apt-add-repository ppa:ubuntu-x-swat/x-updates

sudo apt-get update

sudo apt-get install nvidia-current

2. Then, reboot

3. Done.

Source : http://noob-tech.blogspot.co.id/2015/04/Install-VGA-Driver-On-Ubuntu.html

I had the same problem in Ubuntu 16.10, after upgrading from 16.04. In the xorg.conf file (/usr/share/doc/xserver-xorg-video-intel/), I changed the driver from "intel" to "nvidia".