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Is there a way to adjust lighting step ? I have Lenovo L520, and Fn + Light Up or Down adjusts by 20%, how can I adjust the step to 10% ? it will help me fine tune lighting at my dark room.

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@ఆగస్ట్ It's not a dupe of that one but these two are exact dupes, yet this one here is the oldest. The other two should be closed instead. –  Tom Brossman Oct 8 '12 at 18:22
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yup! you are right amigo . i will do the remaining job then :D –  raaz Oct 8 '12 at 18:25
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8 Answers

Install xbacklight by opening a terminal with Ctrl+Alt+T shortcut and type this:

sudo apt-get install xbacklight

then after installation, type these commands in terminal:

xbacklight = 10
xbacklight = 20
xbacklight = 5

this may help.

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This method worked perfect for me! Other way is: xbacklight -dec 1, or xbacklight -inc 1 (to increase or decrease 1%) –  lepe Dec 13 '12 at 13:06
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As Colin Ian King said, the levels of brightness are hardware related.

Some laptop screens have 8 levels of brightness and new ones have 16 levels.

On Windows OSes you can change the levels with 1% steps, but they will be rounded to the nearest hardware level. It depends on the screen type.

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The brightness levels are generally under ACPI control with the levels defined in firmware. For example the ACPI control method _BCL "Query List of Brightness Control Levels Supported" informs the kernel how many brightness levels are supported. You can't realistically change this.

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You can install xcalib and then type the command:

xcalib -co 50 -a

Use xcalib -h for help regarding it's options.

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Brightness cannot controlled with large precision. I'm afraid that you're stuck with those brightness levels. To be sure, try controlling the brightness using these terminal commands.

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If I go to System Settings, I find an icon labeled 'Screen' If I click on that icon I get a scroll bar that can set the brightness in small percents, How can I get this screen icon to the top bar ( besides clock, or battery indicator ) ? –  Samir Sabri Feb 11 '12 at 9:13
    
What about launchpad.net/indicator-brightness? I haven't tried it since I don't use Unity/GNOME. –  Lekensteyn Feb 11 '12 at 10:17
    
Oh, sorry, thanks but, how to install it ? –  Samir Sabri Feb 11 '12 at 19:25
    
Have a look at askubuntu.com/a/58022/6969 –  Lekensteyn Feb 11 '12 at 21:08
    
It definetely can be controlled in smallest steps in many cases. Please have a look at askubuntu.com/a/205509/43165. –  vines Oct 25 '12 at 0:30
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You could try setting it manually. First you have to get the PCI-ID of the VGA device:

lspci

Then try this (in my case the PCI-Device is 00:02.0)

sudo setpci -s 00:02.0 f4.b=FF

The 2 letters at the end of the Line set the new brightness ranging from 00-FF (0-255)

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If you are using Nvidia Graphic card..you can easily use my new method of brightness changing,and edit values in Code.. theres two files and two options within each one.

find these two lines:

if ( $value > 0.0) { $value = $value - 0.30 };  
if ( $value2 > 1.1) { $value2 = $value2 - 0.08 }; 

change values of ($value > 0.0) & ( $value2 > 1.1) and see whats happens!

meanwhile if you dont want to change values and wish to use my method originally you can change brightness in a wide range and 5 steps. wish you like it

link of method: http://askubuntu.com/a/179063/82136

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This will give you amazing result (if it works successfully for you, of course)

sudo gedit /etc/default/grub

and make the replace the contents of the file by this one

 # If you change this file, run 'update-grub' afterwards to update
 # /boot/grub/grub.cfg.
 # For full documentation of the options in this file, see:
 #   info -f grub -n 'Simple configuration'
GRUB_DEFAULT=saved
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
GRUB_CMDLINE_LINUX=""

 # Uncomment to enable BadRAM filtering, modify to suit your needs
 # This works with Linux (no patch required) and with any kernel that obtains
 # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
 #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef" 

 # Uncomment to disable graphical terminal (grub-pc only)
 #GRUB_TERMINAL=console

 # The resolution used on graphical terminal
 # note that you can use only modes which your graphic card supports via VBE
 # you can see them in real GRUB with the command `vbeinfo'
 #GRUB_GFXMODE=640x480

 # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
 #GRUB_DISABLE_LINUX_UUID=true

 # Uncomment to disable generation of recovery mode menu entries
 #GRUB_DISABLE_RECOVERY="true"

 # Uncomment to get a beep at grub start
 #GRUB_INIT_TUNE="480 440 1"

-------and then run sudo grub-update and then restart

by doing this i could lower my screen brightness to complete 0 like if the monitor was turned off.

[ credits : Vikas Malviya ]

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