Comments on: Adjust LCD brightness from command line

By: nomad

nomad — Thu, 25 Feb 2010 04:03:37 +0000

i installed xbacklight and typed in “xbacklight -set 100″
then it says “No outputs have backlight property”

what’s the problem..??

By: Anaconda

Anaconda — Wed, 24 Feb 2010 12:05:54 +0000

for all of you, who have the “invalid argument” problem. And who can’t change the brightnes value, because you are unable to edit the brightness file.

Install xbacklight (eg. sudo apt-get install xbacklight) and use it to change the brightness value eg.
xbacklight -set 100

Just change the 100 to anything you want between 0-100
In my machine the numbers are not in logical order, but once you know how bright each seting is you can “remember those numbers”, or write a script

And xbacklight does change the brightness value too…

By: ?e??????a

?e??????a — Sun, 17 Jan 2010 02:29:41 +0000

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By: RProgrammer

RProgrammer — Sat, 19 Dec 2009 01:42:10 +0000

Sorry, the forum ate my <> signs

/proc/acpi/video/GFX0/LCD# cat brightness

/proc/acpi/video/GFX0/LCD#

By: RProgrammer

RProgrammer — Sat, 19 Dec 2009 01:38:56 +0000

I have GFX0 instead of VGA on Karmic and I get the Invalid Argument error too.

/proc/acpi/video/GFX0/LCD# echo -n 100 > brightness
bash: echo: write error: Invalid argument
/proc/acpi/video/GFX0/LCD# cat brightness

/proc/acpi/video/GFX0/LCD#

By: Tyrone Dimery

Tyrone Dimery — Mon, 30 Nov 2009 16:32:07 +0000

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By: Benneh

Benneh — Sun, 29 Nov 2009 12:27:40 +0000

Hi Neal Stephenson!

I use Kubuntu 8.04 and the following is working nicely for me:
sudo su

and next:
echo -n 100 > /proc/acpi/video/VGA/LCD/brightness

Hope it helps!

By: ???????? ?????

???????? ????? — Fri, 06 Nov 2009 21:52:42 +0000

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By: Neal Stephenson

Neal Stephenson — Wed, 28 Oct 2009 20:27:22 +0000

got “persmission denied” on xubuntu 8.10 (sudo used! when tried as root in that dir got invalid argument)

when
sudo echo -n 100 > /proc/acpi/video/VGA/LCD/brightness

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By: Dan

Dan — Wed, 14 Oct 2009 02:35:56 +0000

Is there anyway to control the brightness on an LCD panel monitor for a desktop. Mine is too bright and there is no video folder. I’m sure this is possible as when the computer is left idle it gradually dims until it goes blank. There must be a way to dim the screen a set amount.