Brightness setting not remembered on an Asus X54H

Question

So I set the screen brightness using either the function keys or the brightness & lock app. After a reboot or plugging in A/C the brightness goes back to max. When I take A/C off brightness is again reset to maximum. I'd just like Ubuntu to remember what brightness setting I like! Any ideas?

Laptop is an Asus X54H

Answer 1

The tip from leandro on his own question works great for me:

Problem solved by adding acpi_osi=Linux acpi_backlight=vendor to the line that begins with GRUB_CMDLINE_LINUX_DEFAULT= inside /etc/default/grub

My Ubuntu now always remembers its last brightness settings. No need to set my brightness to an arbitrary value through any scripts :)

Answer 2

1) Edit etc/rc.local and add the below line

echo 4 > /sys/class/backlight/acpi_video0/brightness

Where 4 is the 50 % of brightness. 8 is the maximum

2) reboot

If brightness still goes back to max go to step 3

3) In terminal run the following:

sudo -i
mv /etc/init.d/rc.local /root/
update-rc.d rc.local remove
mv /root/rc.local /etc/init.d/
update-rc.d rc.local defaults

If above 3 steps failed to resolve

Then add sleep 10 to rc.local

Example

sleep 10 
echo 5 > /sys/class/backlight/acpi_video0/brightness
exit 0

Answer 3

There are some bug reports on launchpad about this issue, but I don't think there will be a solution anytime soon. Here is one of them: https://bugs.launchpad.net/ubuntu/+source/gnome-control-center/+bug/870805

It does not look like there is a solution besides manually setting the brightness appropriately (or using some automatic script to do so).

Answer 4

Same problem here on clean installation.

First set your desired brightness value with your function keys.

Now you're going to identify it on a number scale by typing in a terminal :

cat /sys/class/backlight/acpi_video0/brightness

keep your value in mind and then go edit config file:

sudo gedit /etc/rc.local

and add the following line right before the "exit 0" line

echo x > /sys/class/backlight/acpi_video0/brightness

where x stand for your desired value.

This way:

.

where 4 is an example of value.

Save the document and exit, now after reboot and ac power plug it will be all fine.

Answer 5

I have the same problem but my laptop does remember the brightness during the connecting and removing the power cord. I faced the problem during the reboots.

Here is the workaround I have done to set the brightness to a value during each reboot.

1. Install xbacklight ( sudo apt-get install xbacklight )
2. Adjust the brightness of display.
3. Open a terminal and run xbacklight -> It will give you the percentage of brightness. In my case it is 53.33
4. Create a file .xbacklight in your home folder and set the execution permission to the file by "chmod +x .xbacklight"

Add following lines in the file

#!/bin/bash
xbacklight -set <brightnes value you got from step 3>

1. Add this file you startup applications.

This fixed my issue but you need to figure out how to do the same for A/C adapter.

I do not know why such pervasive issue is still there in Ubuntu.

Answer 6

1) Add the ikonoba ppa: sudo apt-add-repository ppa:ikoinoba/ppa

2) Install xbrightness-rgbgamma: sudo apt-get install xbrightness-rgbgamma

3) Add xbrightness-rgbgamma 50000 at startup applications (substitute 50000 for a value between 0 and 65535.