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I have a dual boot with Ubuntu 14.04 and Windows, and I have a problem with brightness. When I increase brightness to 1 and I reboot the computer, it has come to be at maximum brightness. I've tried after any reboot and when I start Ubuntu I have to increase it again to 1. Why is it not saving the brightness setting for me? I want to save the current value, not a fixed value.

I added a related line echo 0 > /sys/class/backlight/intel_backlight/brightness and after rebooting it's reset to the maximum again.

My laptop model is Vaio SVF1521DCXW.

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@ Yousef's,@hakermania:I want to save current value Not a fixed value! –  KasiyA Jun 10 at 16:24
    
I Think after you enter the Fixed Value it will save the future Changes, if it doesn't, i guess it's related to BIOS, as BIOS Saves the Brightness Settings too, You Could Try Updating It. –  Yousef's Jun 10 at 16:27
    
Try, not Sure, but Becarful to don't loose Power During Update, you will Turn your Laptop into a Brick, do this as a last Attempt, Maybe it's not related, Also does it Work in Windows Correctly? –  Yousef's Jun 10 at 16:32
    
Yes it is work in windows correctly. –  KasiyA Jun 10 at 16:35
2  
Can you add the model of the laptop to your question? Thanks! –  Jorge Castro Jun 10 at 16:49

2 Answers 2

make a file like fixMaxBrightness.sh

copy all these line to it, make it executable by chmod +x fixMaxBrightness.sh and run it by this command sudo ./fixMaxBrightness.sh restart your system.


#!/bin/bash
#this script are going to get last change screen Brightness
#and put it in /.FixBritness
#this folder is in home directory that the following line make it 
mkdir $HOME/.FixBritness
cd $HOME/.FixBritness

#make two another script that put current brightness in "currntBritness" file, 
#and it must run when system is going down
cat > getBritness.sh <<_EOF_
#!/bin/bash
cat /sys/class/backlight/acpi_video0/actual_brightness > $HOME/.FixBritness/currntBritness
exit 0
_EOF_

#to get last brightness that saved in "currntBritness" file
#and put it in system brightness file 
cat > putLastBritness.sh <<_EOF_
#!/bin/bash
cat $HOME/.FixBritness/currntBritness > /sys/class/backlight/acpi_video0/brightness
exit 0
_EOF_

# create currntBritness file and put zero to defult value
touch currntBritness
echo 0 > currntBritness

chmod 755 getBritness.sh
chmod 755 putLastBritness.sh
#put in /etc/init.d/ because these file will use in /etc/rc1 through rc6
mv getBritness.sh /etc/init.d/
mv putLastBritness.sh /etc/init.d/

#make a symbolic link to  getBritness.sh that get brightness when:
#shutting down
ln -s /etc/init.d/getBritness.sh /etc/rc0.d/S11getBritness.sh
#and restart
ln -s /etc/init.d/getBritness.sh /etc/rc6.d/S11getBritness.sh


#symlink to put last brightness when system start.
ln -s /etc/init.d/putLastBritness.sh /etc/rc1.d/S66putLastBritness.sh
ln -s /etc/init.d/putLastBritness.sh /etc/rc2.d/S66putLastBritness.sh
ln -s /etc/init.d/putLastBritness.sh /etc/rc3.d/S66putLastBritness.sh

exit 0
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up vote 0 down vote accepted

I had another folder named acpi_video0 in this location /sys/class/backlight/

And I add following command at the end and before exit 0 into
sudo gedit /etc/rc.local file:

echo 0 > /sys/class/backlight/intel_backlight/brightness
echo 0 > /sys/class/backlight/acpi_video0/brightness

It's worked for me but if someone know that how can I get current brightness and save it into this file to effect it at next restart. I mean is save automatically current bright in above file.

I find one here answered by @user207402 but I don't understand how can I use it. It's not a clear for me.

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