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I am using Fedora 13 and whenever I Restart or Logoff on my laptop. The screen brightness resets to its maximum value. I am not aware of this problem. Can anyone tell me why this is causing and what is the solution for keeping it's to a constant value at all time?

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Curiously, how do you change the brightness? – Tshepang Mar 17 '11 at 10:16
@Tshepang : I change it simply by pressing Fn+F4 or Fn+F5 Keys. As it's default keys for this and marked symbol for that in my Dell Laptop. – Vikas Patidar Mar 17 '11 at 10:19
You need to say what exact laptop model you have, and also what graphics card. – Gilles Mar 17 '11 at 20:26
up vote 2 down vote accepted

You might want to check out the following bugs for possible explanations:

It seems that your problem is likely being caused either by gdm or by a bug in gnome-power-manager. If it's the former, then the last bug above points to a discussion that contains a possible solution (see the post by swmail), however, I don't know if it will work in your case (let us know what happens, and we'll work from there ...).

If it's gnome-power-manager causing the problem, it seems that the bug still hasn't been fixed.

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The solution is to use the following command at startup:

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

Probably you can have a look at this link, which provides a workaround till you get a fix from distribution.

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You can make a service file and in its [Install] section write


And in [Service] section write

echo 3 > /sys/class/backlight/acpi_video0/brightness

And it will do the trick.

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Please could you edit your post to use formatting, so that you make it clear what someone should write, where. Start each line of code with 4 spaces. Use backticks to format code inline. – roaima Jun 21 '15 at 16:52

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