****WARNING: this will only work for releases up to Feisty. It still might be useful info though, so feel free to read through it :)****
For those people who use their laptop more on the battery than the power supply, one of the best ways to save yourself some power is to lower the brightness level of the monitor.
The first thing you need to do is to start up the sony_acpi software. Open up a terminal & type..
sudo modprobe sony_acpi then press the enter key to execute the command.
This will create 2 new files within the sony directory called brightness & brightness_default.
You can check that these have been created by typing ls /proc/acpi/sony into the terminal.
The next thing that you need to do is to change ownership of the files by typing..
sudo chown root /proc/acpi/sony/brightness
sudo chown user_name /proc/acpi/sony/brightness
You need to change user_name to whatever name you use to log into Ubuntu with.
WARNING: If you were to restart your computer now, the files wouldn’t be there any more until you do everything up to this point again. The files don’t get created until sony_acpi is started with the modprobe command & are deleted again if you close down the terminal.
Now for the fun part 😀
In the terminal type..
sudo echo “1” > /proc/acpi/sony/brightness
You’ll notice that the brightness level on your monitor goes way too dark. Don’t worry too much about this as it would be set back to the normal level on a restart anyway.
To get back to the prior level just type..
sudo echo “8” > /proc/acpi/sony/brightness
Your terminal should now look something like this..
The number in the line is the brightness level that your telling the laptop to use; 1 is the darkest level & 8 is the lightest.
Have a mess about with this & try any of the numbers between 1 & 8 to find one that you will be comfortable with using most of the time.
Now that you’ve found the right level to use, you can set it as the default level. It’s worth noting that this sets the brightness level directly within your laptops bios. It has nothing to do with Ubuntu & as such will be the default brightness as soon as your laptop is powered up.
To set the desired default brightness level, in the terminal type..
sudo chown root /proc/acpi/sony/brightness_default
sudo chown user_name /proc/acpi/sony/brightness_default
(Not forgetting once again to change user_name to whatever name you use to log into Ubuntu with)
echo “5” > /proc/acpi/sony/brightness_default
(change the 5 to whatever level you decided on when testing)
That’s it! Now re-start your computer to see the change & it should be at a darker level than previously.
There is a way to have the computer modprobe sony_acpi automatically on start up & change the ownership of the files for you. There’s not much point in doing this though, as our ultimate goal is to setup the Fn+F5/F6 keys to allow us to change the brightness on demand & the sony_acpi patch will do all that for us when it’s installed.