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Cannot control brightness

asked 2015-11-27 08:00:31 -0500

salmankhan gravatar image

updated 2015-11-27 08:32:39 -0500

mether gravatar image


I am using fedora22. I was able to adjust brightness using Fn keys and from brightness slider. Suddenly, today I cannot adjust brightness using Fn keys from keyboard or from slider. Also, the brightness slider under 'settings->power' is disappeared. I don't know how it happened, but i remember installing dconf-editor today morning and changed only the auto suspend settings. . How can i adjust brightness again? Thanks in advance.

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answered 2016-01-09 07:33:28 -0500

Sesivany gravatar image

When it stopped working did you just the slider to adjust brightness? Slider lets you pick any value for the settings and sometimes the driver lies about what values it supports. It only supports multiples of 5 between 1 and 100, but the driver says it can be any number. Fn keys usually jump up by 5 or 10, so the problem doesn't occur there. But when you use the slider, it lets you set e.g. 27 and you're on an invalid value. Then even the Fn keys don't work because jumping by 5 or 10 keeps you on invalid values. To fix it, you need to set a valid value by xrandr for instance.

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answered 2016-01-08 03:13:44 -0500

Have you tried with xrandr to adjust brightness?

By issuing following command you'll able to adjust brightness for the logged session.

xrandr --output $(echo xrandr -q | grep ' connected' | cut -d ' ' -f 1) --brightness [ Brightness value from 0 (black) to 1.0(full bright) ]

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Asked: 2015-11-27 08:00:31 -0500

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Last updated: Jan 09 '16