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As many other Ubuntu users several days ago I’ve upgraded my Feisty to Gutsy at my Dell Inspiron 1501.
Unfortunately many things that worked for me in Feisty doesn’t work in Gutsy just after upgrading. Among them are: suspend/hibernate and brightness adjustment. At this moment I’m trying to get these features working and certainly share results here but not workable brightness adjustment really disturbed me. So, until I didn’t find a solution how to adjust LCD brightness with keyboard, there is nice workaround: execute the following command with root rights (sudo -s to get it):
echo -n 100 > /proc/acpi/video/VGA/LCD/brightness
This will make you LCD screen as bright as possible and you can proceed with your work (like me 
). To lower brightness just replace 100 with another value like 62 and watch the results.
Hope it helps!
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Nice tip
how?
Hi aruvoski,
In your Ubuntu:
Applications -> Accessories -> Terminal
Then type `sudo -s` and enter your password. After you’ve got prompt like
~#, you can type:echo -n 100 > /proc/acpi/video/VGA/LCD/brightnessto adjust LCD brightness where 100 is maximum value and 62 is minimum.
Hope it helps!
P.S. You’re welcome to ask any related questions here
Pay attention that you might have GLX instead of VGA as in:
/proc/acpi/video/GLX0/LCD/brightness
Anyway, this is a ‘cool’ tip. Thanks for it!
oh good lord THANK YOU
i have been trying to figure this out for weeks.
YAY BRIGHT SCREEN AGAIN!!
Hey everybody, thanks for your comments!
I have a Dell Latitude C610 and I’ve tried running the line in Ubuntu tho I had to modify as my line is /proc/acpi/video/VID/LCD/brightness. But it’s saying the command is unknown.
Hello Rasha,
try this:
sudo -sorsuthen
echo -n 100 > /proc/acpi/video/VID/LCD/brightnessNo luck for me
# echo -n 50 > /proc/acpi/video/VGA/LCD/brightness
bash: echo: write error: Invalid argument
What could be wrong?
turn off acpi and it will work with fn keys
it might only work on opensuse. when you do this kpowersave doesnt work
Try running cat /proc/acpi/video/VGA/LCD/brightness
This will show supported brightness levels.
Running it on my monitor gives
root@Gateway-M-Series:/home/animatt# cat /proc/acpi/video/VGA/LCD/brightnesslevels: 100 37 12 25 37 50 62 75 87 100
current: 12
Thanks for posting this info. Every day, I learn something new about using linux. Much more fun than M$ Win!
Seems to me this could easily be put in a script that would read the current setting and go up or down depending on which name it was called with.
I’m going to work on it for myself and post it back here in case anyone else is interested.
Can all of the hardware be controlled via the /proc dir?
Thanks again for the pointer.
The following is working nicely for me:
#!/bin/sh
# adjust lcd brightness on Dell Inspiron 1501 – 080303 Alex P Janssen Jr – alex@ourwoods.org
# INSTRUCTIONS:
# Save this script to a file named brightup.sh in /home/yourusername/bin
# Make it executable: chmod +x brightup.sh
# Save yourself having to run it in a terminal and enter your password each time
# edit sudoers: sudo visudo
# add to sudoers: yourusername ALL=(ALL) NOPASSWD:/bin/bash
# save and exit
# link brightup and brightdn to brightup.sh:
# ln -s /home/yourusername/bin/brightup.sh /home/yourusername/bin/brightup
# ln -s /home/yourusername/bin/brightup.sh /home/yourusername/bin/brightdn
# Add a couple of custum launchers to your panel ( I run Gnome )
# Right-click the panel and select Add to Panel
# Click Custom Launcher
# Type=Application, Name=Darker, Command=sudo bash -c /home/apjjr/bin/brightdn
# Select a down-arrow for an icon and Close
# Do the same for brightup, except set the name to Lighter and pick an up-arrow
#
# check our id
#echo `id`
ourname=$0
ourname=`basename “$ourname”`
xx=`cat /proc/acpi/video/VGA/LCD/brightness | grep current | cut -c 9-`
curbright=`echo $xx`
# check process name and current brightness setting
#echo “${ourname},${curbright}:”
case $curbright in
0) # after boot my brightness value is 0
# echo “12″
echo -n 12 >/proc/acpi/video/VGA/LCD/brightness
;;
12) if [ "$ourname" = "brightup" ]; then
#echo “12 to 25″
echo -n 25 >/proc/acpi/video/VGA/LCD/brightness
fi
;;
25) if [ "$ourname" = "brightup" ]; then
#echo “25 to 37″
echo -n 37 >/proc/acpi/video/VGA/LCD/brightness
else
echo -n 12 >/proc/acpi/video/VGA/LCD/brightness
fi
;;
37) if [ "$ourname" = "brightup" ]; then
#echo “37 to 50″
echo -n 50 >/proc/acpi/video/VGA/LCD/brightness
else
echo -n 25 >/proc/acpi/video/VGA/LCD/brightness
fi
;;
50) if [ "$ourname" = "brightup" ]; then
#echo “50 to 62″
echo -n 62 >/proc/acpi/video/VGA/LCD/brightness
else
echo -n 37 >/proc/acpi/video/VGA/LCD/brightness
fi
;;
62) if [ "$ourname" = "brightup" ]; then
#echo “62 to 75″
echo -n 75 >/proc/acpi/video/VGA/LCD/brightness
else
echo -n 50 >/proc/acpi/video/VGA/LCD/brightness
fi
;;
75) if [ "$ourname" = "brightup" ]; then
#echo “75 to 87″
echo -n 87 >/proc/acpi/video/VGA/LCD/brightness
else
echo -n 62 >/proc/acpi/video/VGA/LCD/brightness
fi
;;
87) if [ "$ourname" = "brightup" ]; then
#echo “87 to 100″
echo -n 100 >/proc/acpi/video/VGA/LCD/brightness
else
echo -n 75 >/proc/acpi/video/VGA/LCD/brightness
fi
;;
100) if [ "$ourname" != "brightup" ]; then
echo -n 87 >/proc/acpi/video/VGA/LCD/brightness
fi
;;
esac
exit 0
That’s it.
Alex
Hello. Here is another way to do this. I add in the file ~/.bashrc :
Bup ()
{
FILE=/proc/acpi/video/VID/LCD/brightness
current=`cat $FILE | grep current | cut -c 10-`
prev=12
for i in `cat $FILE | grep levels | cut -c 17-`; do
if [[ $i -eq $current && "$1" == "-" ]]; then
echo -n $prev > $FILE
break;
elif [ $i -gt $current ]; then
echo -n $i > $FILE ;
break;
fi;
prev=$i
done
}
Bdown (){ Bup -; }
(Just make sure the line FILE=/proc/acpi/video/… points to your correct file.)
This way, I can type in a terminal “Bup” or “Bdown” to set the brightness up or down.
Greetings.
BRIGHTNESS on UBUNTU:
This has worked for me in the directory, for me
/proc/acpi/video/OVGA/DD03$
and I did the command
echo -n 100> brightness
in my directory.
Don’t forget to change the rights and owner for the file brightness
Thanks for this artiomix:
”
” echo -n 100 > /proc/acpi/video/VGA/LCD/brightness
to adjust LCD brightness where 100 is maximum value and 62 is minimum.
Hope it helps!
thank you so much!!! you saved my eyes from burning!
guys do this work on windows?
i need to know pls make me know the fast you can my email is
elmenoldr@hotmail.com
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.
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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??? ??? ??????? ????????? ?? ????. ??? ???????? ?????? ??????????????.
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!
Hello, I just found your website while searching around online as I’m seeking some information on LCD TVs!. It’s a very interesting site so I bookmarked your site and intend to return tomorrow to enjoy a more detailed look when I have more time.
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#
Sorry, the forum ate my <> signs
/proc/acpi/video/GFX0/LCD# cat brightness
<not supported>
/proc/acpi/video/GFX0/LCD#
??? ???????? ???????????????, ?? ??? ??????? ??? ?? ???????????? ????? ???????? ?????? ????? ?????-?? ?????.
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…
i installed xbacklight and typed in “xbacklight -set 100″
then it says “No outputs have backlight property”
what’s the problem..??
Hi Guys,
Okay – those guys having problems… Type in:
cat /procacpi/video/VGA/LCD/brightness
In that above line, LCD may be something different – mines LLCD. Anyway, there’s the possibility that yours isn’t on a scale from 0 to 100. Mine goes from 0 to 15. So if you’re looking at your monitor and it’s already pretty bright, and you’ve run that command above, that’s probably going to be your maximum value.
So go to the original command, and alter your values to match.
Regards,
Nevyn.
i keep getting “bash: /proc/acpi/video/GLX0/LCD/brightness: No such file or directory”
but it is there, i checked by browsing the file system, but the file is read-only
anything i can do?
One note: If you don’t have /proc/acpi/video, do this:
sudo modprobe video
Now you have.
Hi,
I am also getting “No outputs have backlight property”.
After installing back light. What should i do??
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hey i am sing ubuntu 10.04 version. my system brightness is not changing with Fn key.
/proc/acpi/video/VGA/LCD/brightness is not there. there is /proc/acpi/video/GFX0/DD01/brightness file. but when i followed with echo -n /proc/acpi/video/GFX0/DD01/brightness it is saying that echo is invalid arguement… please help me .. i am facing problem to my eyes with high brightness.
If you use gnome, you could just add Brightness Applet to you Panel
Thanks – it works!
Thank you for shfwaring youwr admin would get ready a severely beneficial write-up I congratulate.
hi i tried it but it did not work and it says root@me~#
Check my tool for the brightness adjustment.
https://github.com/akozadaev/xbright
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It worked for my HP Pavilion tx 1000 / 1215 laptop.Thanks buddy.