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How to set brightness below minimum?

asked 2014-05-09 19:42:56 -0500

rflribeiro gravatar image

I have Fedora 20 x86_64 Mate Desktop at Dell Latitude E6430 and minimum screen brightness is still too high. I tried to setup a value under 0 using /sys/class/backlight/acpi_video0/brightness, since I'm using video.use_native_backlight=1 in boot parameters, xbacklight and xrandr, with no success. Is there a way to dim brightness under 0?

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I don't have an answer yet, I'm trying to figure out the same thing... If possible I'd like to be able to turn the screen righ toff while listneing to a music playlist to conserve battery.

tw0shoes gravatar imagetw0shoes ( 2014-12-07 14:45:26 -0500 )edit

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answered 2014-12-19 07:39:15 -0500

jayaura gravatar image

updated 2014-12-19 08:35:08 -0500

That depends on your hardware and your kernel version. The answer was more simpler before 3.17. Natural way in an intel system is to run the command below as root. sudo doesnt work.

echo 100 > /sys/class/backlight/intel_brightness/brightness

Choose appropriate value for the brightness you need. Choose the value you want instead of 100. You can get the maximum value that you can use with

cat /sys/class/backlight/intel_backlight/max_brightness

If its not intel, check what folder you have in /sys/class/backlight folder. For example, it a sony vaio, it was something like acpi_backlight though I dont remeber it correctly.

But things changed a little bit from 3.17, which we have in Fedora 21. Only for intel though. Folks at OTC decided to keep a minimum level for the brightness value for some reason. So now you cant reduce below the minimum level governed by the userspace.

But if you so badly want it, you can. Thats the best part in linux. Though a little bit complicated. This will involve recompiling the kernel. You can follow the instructions at to get this done for you.

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echo 10 > /sys/class/backlight/intel_backlight/brightness does it for me.

deadrat gravatar imagedeadrat ( 2015-01-06 12:11:56 -0500 )edit

answered 2014-12-08 14:10:26 -0500

In Windows there is an app called F.lux I do not know if the app is compatible with Fedora

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Asked: 2014-05-09 19:42:56 -0500

Seen: 1,329 times

Last updated: Dec 19 '14