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One of the forum community members created this howto/faq, due to formatting problems, is was deemed unacceptable for the forum, but due to all the effort th Forum Community member put in to create this, I thought is was a shame that this information be relegated to the Jail, where no one else can benefit from this information.

The problem is spreading

Screen brightness on laptops, has been a continuing problem through past releases, there have been many bugs reported about this problem, this is by no means a definitive list, but these are the bug reports I've found so far:

#910536 reported by Otto Kekäläinen on 2012-01-01 - the screen is OK in the boot menu (non-X) but as soon as X starts, the backlight of the screen turns off making the screen almost black, and thus unusable.. Pressing Fn+Left Arrow does not increase screen brightness.

#571421 reported by Chris van Hoof on 2010-04-28 - brightness hotkeys not functional

#543294 reported by KlavKalashj on 2010-03-21 - Brightness moves in random direction a couple of times, then stop responding.

#518002 reported by Wolfgang Kufner on 2010-02-06 - backlight dimming not working.

#515214 reported by travauxpublics on 2010-01-31 - i have no control (hardware or software) of brightness. The keyboard does not help any more, like Ubuntu 10.04 does not recognize this function.

#513921 reported by Rolf Leggewie on 2010-01-28 - I found out that the keys for adjusting display brightness (Fn+F5, Fn+F6) don't work as expected.

#429942 reported by Spock112 on 2009-09-15 - some of the hotkeys don't work correct.

#399911 reported by Sergey on 2009-07-15 - brightness key presses are ignored.

#347623 reported by pittipatti on 2009-03-23 - The Samsung Q45 does not send key release events for several Fn-keys.

#295251 reported by anwe0212 on 2008-11-07 - brightness keys block keyboard and produce all-or-nothing effect.

#284319 reported by Dirk on 2008-10-16 - The buttons for controlling the brightness (Fn F9/F10) don't work.

it seams that the bug didn't even spared the Mint distribution

#577514 reported by Timmi on 2010-05-08 - The Fn keys are not detected on install, and don't work with ANY of the utilities available in Synaptic. )Most importantly (to me) is brightness control.

So basically all the bugs are beeing reported by people that need to change their brightness settings and find out that they have no controll over their machine.

This issue is persistent in other parts of Ubuntu Community like on AskUbuntu.com

Question #49778 asked by nibot on Jun 21 2011 - I am unable to adjust the display brightness. Pressing Fn-Home and Fn-End brings up the display brightness on-screen display and the indicated level increases or decreases as it should. But the actual display brightness does not change.

Question #104112 asked by MartinDK on Feb 14 2012 - The system keys for changing brightness are Fn+F7 and Fn+F8, respectively, but nothing happens - I can't change the brightness.

in other parts of the web i found the following (all Ubuntu related):

BigResource.com - I installed ubuntu 11.04. Everything works fine except the fn + f2 and fn +f3 which decreases and increases the brightness respectively.

SuperUser.com - I installed ubuntu 10.10 64 bit on it. It works great -- the only problem is that the brightness controls on the keyboard don't work.

Bunkus.org - 1.04 Natty. Everything went fine. Unfortunately pretty much all of my special keys (backlight, volume, suspend, WIFI) stopped working after the obligatory reboot.

Repetitive threads on the Ubuntu Forums

So the address for all the repetitive threads is:

Ubuntu Forums > The Ubuntu Forum Community > Main Support Categories > Desktop Environments

Not able to change screen brightness on my laptop {3 replies} - laptop with nvidia graphics card. i have updated the restricted drivers but the function keys wont work, please someone help, its difficult to work with full brightness [Opened on]: January 30th, 2012 - {Last Post on}: January 30th, 2012

Brightness Slider Doesn't Actually Alter Brightness {5 replies} - The slider moves when I press the buttons, but the actual screen's brightness stays the same. {Opened on}: January 11th, 2012 - [Last Post on]: May 8th, 2012

Screen bright set {1 reply} - can I set something to make my Toshiba laptop to boot with a 50% screen brightness instead of 100% ? {Opened on}: December 20th, 2011 - {Last Post on}: December 20th, 2011

Ubuntu 11.10 Brightness Control (Sony VAIO VPCEG1BFX/W) {2 replies} - I cannot change the brightness control from my laptop {Opened on}: November 30th, 2011 - {Last Post on}: December 2nd, 2011

Changing brightness does not work in Ubuntu 11.10 after upgrading {36 replies} - Unity as a desktop environment,increasing and decreasing brightness via fn+f5 and fn+f6 does not worked any more. {Opened on}: November 4th, 2011 - {Last Post on}: 2 Hours Ago

{solved} Screen brightness after screen lock (21 replies} - Sometimes after the screen has been locked and I've entered my password, the screen has minimal brightness and the function keys no longer do anything. {Opened on}: November 1st, 2011 - {Last Post on}: December 16th, 2011

{all variants} Brightness control hook {no reply} - I'd like to use laptop brightness keys to control not only the laptop screen brightness, but also the external monitor brightness {Opened on}: September 19th, 2011 - {Last Post on}: ---

{xubuntu} FN Keys of Laptop brightness does not work {5 replies} - HP Probook 4510S and the FN Keys of brightness only works when i on the login screen (gdm). Until i enter to my desktop the FN Keys stop Working. This is a XFCE Issue? I have another Laptop, a IBM THinkpad X40, with the same Xubuntu 11.04 and the FN Keys works perfect! Even the keyboard light Works! {Opened on}: July 25th, 2011 - {Last Post on}: July 26th, 2011

{ubuntu} function key does not work correctly {3 replies} - When I change the brightness of my screen I press the function key then then up and the screen gets dimmer, but the pop up box in the top right hand corner shows its getting brighter and vica versa. The biggest issue I have is the monitor function key. To use my second monitor I have to turn off my laptop then turn it back on. {Opened on}: July 19th, 2011 - {Last Post on}: August 13th, 2011

{ubuntu} Brightness problem in Ubuntu 11.04 {no reply} - it was too dark. I tried to use fn key to change the brightness but none did it. {Opened on}: July 13th, 2011 - {Last Post on}: ---

{ubuntu} How to dim the lightness of screen {6 replies} - I used the keyboards keys but it change nothing although I decrease it to the end {Opened on}: June 8th, 2011 - {Last Post on}: June 10th, 2011

{ubuntu} Multitude of problems with Gnome3 -- Empathy, keyboard, VLC, brightness, sound, Bansh {6 replies} - The laptop screen brightness setting gets reset frequently and the brightness gets turned up automatically. {Opened on}: May 29th, 2011 - {Last Post on}: May 30th, 2011

{ubuntu} brightness control problem with ubuntu 10.10 {1 reply} - I can not control my brightness by up& down keys {Opened on}: May 25th, 2011 - {Last Post on}: May 25th, 2011

(64 bit} Nov8th Lucid update breaks screen brightness {no reply} - for a couple of versions now the fn+x key combos to increase and decrease the screen brightness have worked fine. Today's update seems to have broken this. {Opened on}: November 8th, 2010 - {Last Post on}: ---

Brightness applet does not work {2 replies} - tried adding the brightness applet to a panel, but does nothing when I try to fiddle with the slider. And one more thing, when I unplug my laptop from the power adapter, it doesn't scale down the brightness automatically, the same way when I plug it back in, the brightness doesn't scale up. {Opened on}: November 1st, 2010 - {Last Post on}: November 4th, 2010

Brightness control problem {6 replies} - It is shown a brightness meter in the screen that is increasing/decreasing but actually the brightness does not increase/decrease. {Opened on}: October 22nd, 2010 - {Last Post on}: October 23rd, 2010

{64 bit} can't adjust my screen brightness to maximum {no reply} - when I run my laptop on batttry, the brightness is so dim that i can barely see and I cannot increase the brightness.. {Opened on}: October 17th, 2010 - {Last Post on}: ---

{ubuntu} brightness applet bug {3 replies} - basically, the sliding bar comes up when i click the applet button but the moment i click on the slider trying to adjust the brightness the bar simply disappears.{Opened on}: July 7th, 2010 - {Last Post on}: February 19th, 2011

{ubuntu} how to adjust brightness permanently? {1 reply} - how can i set the applet so i don't have to do it every time i boot my laptop ? {Opened on}: May 21st, 2010 - {Last Post on}: May 21st, 2010

{ubuntu} Fn+Up,down or applet for gnome brightness failure[URL="http://ubuntuforums.org/showthread.php?t=1417619|{no reply}]] - nor i can use fn+up or fn+down to adjust the brightness.{Opened on}: - {Last Post on}:

{ubuntu} Problem with the brightness on my laptop {no reply} - If i use my function laptop keys to manage the brightness it doesn work {Opened on}: February 27th, 2010 - {Last Post on}: ---

{ubuntu} Laptop Backlight Brightness Wont Work {1 reply} - The function keys seem to be detected alright, but when I press them I get the notification that the brightness is going down but nothing happens. {Opened on}: May 5th, 2010 - {Last Post on}: May 5th, 2010

[ubuntu] turn down screen brighter {2 replies} - the panel application is no different than using the fn key, and does not provide any further decrease in brightness. {Opened on}: February 16th, 2010 - {Last Post on}: February 18th, 2010

{ubuntu} brightness issue with 9.10 {no reply} - By the time i get to the log in screen after starting the computer the display is rather dark, i can simply make it bright by using the Fn and up arrow keys. However if i log out the log in will be as dim as it was when i first logged on {Opened on}: December 10th, 2009 - {Last Post on}: ---

{ubuntu} Desktop Monitor LCD Brightness {no reply} - The Power Manager Brightness Applet seems only to apply to laptops! Even then, I have never successfully seen this feature function on any laptop or desktop as of yet. {Opened on}: October 14th, 2009 - {Last Post on}: ---

{ubuntu} Brightness Issue[ {3 replies} - My display Brightness is very very dark and i can't make it bright. {Opened on}: September 15th, 2009 - {Last Post on}: September 19th, 2009

{ubuntu} Changing Brightness Levels {5 replies} - I have a laptop on which the Fn key doesn't work.As I move the slider on the brightness applet, nothing's happening."[/COLOR] [Opened on]: September 18th, 2009 - [Last Post on]: September 18th, 2009

{kubuntu} Weird LCD brightness problem {2 replies} - the main problem is that LCD brightness is not set to the level given in the profile settings. It rather behaves arbitrarily {Opened on}: June 21st, 2009 - {Last Post on}: November 14th, 2010

[ubuntu] Making the screen brightness setting stick {2 replies} - ubuntu resets the brightness {Opened on}: March 11th, 2009 - {Last Post on}: May 1st, 2009

[ubuntu] Screen Brightness and Dual Screen. Need Help. {no reply} - when I login or re-open the lid, the brightness of the screen is always at the lowest level, so I have to increase the brightness {Opened on}: February 19th, 2009 - {Last Post on}: ---

{ubuntu} Default Screen Lightness {2 replies} - But when I log in or close and open the lid, the screen lightness is always at the lowest level, you have to change it. {Opened on}: February 18th, 2009 - {Last Post on}: February 18th, 2009

{kubuntu} Laptop LCD Brightness"http://ubuntuforums.org/showthread.php?t=1067171|{no reply}]] - My laptop's function button doesn't work under Ubuntu. {Opened on}: February 12th, 2009 - {Last Post on}: ---

[ubuntu] How to set the default level of LCD brightness ??? {3 replies} - Can ubuntu auto set the self-defined level of LCD brightness(backlight level) when powered? If can... how!? {Opened on}: November 15th, 2008 - {Last Post on}: October 3rd, 2010

[gnome] Changing brightness adjustment action {no reply} - I have brightness Fn + key adjustments on my laptop. They don't work. {Opened on}: September 30th, 2008 - {Last Post on}: ---

[kubuntu] Gateway MT3422 brightness and suspend issues {1 reply} - I have had issues earlier with the GNOME setup, where the brightness keys on the keyboard were never recognized. {Opened on}: July 1st, 2008 - {Last Post on}: August 31st, 2008

[ubuntu] I want to adjust the brightness of my laptop monitor {1 reply} - In 7.10 It's so bright but in 8.04 it's so dark.{Opened on}: April 26th, 2008 - {Last Post on}: April 27th, 2008

Compiling a list of Workarounds

Workaround 1: - reconfiguration of the "xorg.conf" file (the "log" file of the "nVidia X Server" manager)

I found the solution in this thread , or more precisely this post. The post was also referred to on this UbuntuGuide.net article.

There are 2 steps to do this Workaround

Step 1: you have to access the file with writhing priviledge, since it belongs to user "root". And since "root" in Ubuntu does "not" officially exist (no way to use the su or su- commands, yet the files for the user exist), you have to use the "sudo" command in a terminal (press alt+ctrl+T to open one)

• sudo gedit etc/X11/xorg.conf

where gedit is your advanced version of notepad One other thing you should consider is that the navigation in the terminal is case sensitive. If you use

• sudo gedit etc/x11/xorg.conf

your gedit will open with an empty blank file and when you will try to save that file, you will be greeted by a warning message telling you that the file does not exit. Use UpperCase "X" in the path of the command and you will open the existing file which you have to edit.

Step 2: you will notice that the file contains lines of command texts, grouped into paragraphs called "sections" that each have a name. Look for Section "Devices" paragraph and insert the line of command text

• Option "RegistryDwords" "EnableBrightnessControl=1"[/quote]I think "RegistryDwords" is the library accessed and "EnableBrightnessControl=1" is for giving a positive boolean value to the variable.

After restarting your system, your {Fn} keys have authority over your brightness settings. I've seen some posts cheering this method...

WorkAround #2 - dude with Samsung Laptop {Solved}

This one did it for me! I am so happy! I now have better contrast then i had in Windows 7 ... and back then i was so unhappy thinking that Samsung didn't do a good job with the LCD of this monitor... Praized be the Lord!

This time God worked throw Greg Kroah and "http://linuxtweaking.blogspot.com/2011/11/enabling-samsung-laptop-backlight.html"][COLOR=Blue] 'LinuxTweaking' from BlogSpot.com

He downloaded "http://dl.dropbox.com/u/16953763/Ubuntu%2011.10%20Samsung%20Laptop/Makefile"]"[COLOR=Blue]Makefile " and "http://dl.dropbox.com/u/16953763/Ubuntu%2011.10%20Samsung%20Laptop/samsung-laptop.c"]"[COLOR=Blue]samsung-laptop.c " files from DropBox.com from the terminal, using the "wget" command, and stored the files in a folder he had created before.

[code] mkdir samsung

cd samsung

wget http://dl.dropbox.com/u/16953763/Ubuntu%2011.10%20Samsung%20Laptop/Makefile

wget http://dl.dropbox.com/u/16953763/Ubuntu%2011.10%20Samsung%20Laptop/samsung-laptop.c [/code]He then used the "dmidecode" command to find out the model of his laptop...

[code] sudo dmidecode -s system-product-name [/code]...so that he could fill it in the "dmi table" he just downloaded (samsung-laptop.c). I used "gedit" to temporarly note the code of my product.

[code] gedit samsung-laptop.c [/code]in the samsung-laptop.c file he modified an entry [quote] { .ident = " demidecoded product name " .matches = { DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), DMI_MATCH(DMI_PRODUCT_NAME, " demidecoded product name "), DMI_MATCH(DMI_BOARD_NAME, " demidecoded product name "), }, .callback = dmi_check_cb, }, [/quote]then, he set out to build the samsung-laptop.ko from the edited samsung-laptop.c file, using the "make" command [code] make [/code]furthermore, he replaced the existing module [code]

• sudo cp samsung-laptop.ko /lib/modules/$(uname -r)/kernel/drivers/platform/x86/ sudo depmod -a

[/code]... and added "acpi_backlight=vendor" instruction to "grub" (not sure what module is that) using [code]sudo gedit /etc/default/grub[/code]more specifiicaly in the line [quote]GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"[/quote] resulting in something like "quiet splash acpi_backlight=vendor "

lastly, he updated grub using [code]sudo update-grub[/code]and that was the whole procedure. I fallowed it and my [Fn] keys worked. More then that, now i can change the master settings in nVidia X Server as well, plus, i don't get that nasty error message displayed each time i log in :)[/QUOTE]I thought i was going to make a list of ~12 WorkArounds... when in fact it took me more time to write all this post in BBcode then to actually fix my machine

Hope i was informative, and i hope this bug gets fixed with other marks of laptops in future releases...