# screen brightness [SOLVED]

## Recruit0

I'm using XFCE. How do I adjust the brightness? My brightness keys (Fn + Up/Down) don't work... I checked with xev and apparently the Fn key isn't being detected at all.Last edited by Recruit0 on Wed Jun 11, 2008 6:46 pm; edited 1 time in total

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## ewaller

What is your chipset.  Often there will be a /proc entry which, when read, will tell you your (backlight?) brightness.  If you write to it, it will set the backlight brightness.

I assume you are describing an LCD display, and not the black level of a CRT.

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## pappy_mcfae

Does the screen appear to be blinking, like it's trying to dim, but can't? If so, then you need to disable LCD backlight support in your kernel. Before you do anything else, check to make sure your kernel isn't set up to support the backlight.

Blessed be!

Pappy

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## pdw_hu

Btw: the Fn key by itself won't produce a keycode, but pressed together with an Fn-combination (for example the brightness) it'll display that keycode.

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## Recruit0

I have Intel GM965. Yes I have a LCD display (laptop).

My screen doesn't appear to be blinking... At first I thought backlight support was needed because I didn't have a /sys/class/backlight directory but now I have one and there's nothing in it. I tried recompiling my kernel with backlight support but doesn't seem to do anything   :Confused: 

My brightness keys aren't working at all then. I tried xev with Fn + Up/Down and nothing comes up. Is there a way to do it manually? I was looking into editing some file but idk what file to edit... Stuff on google says to edit some file in the /sys/class/backlight directory but I don't have anything in there.

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## kd5bjo

On my laptop, I can set the backlight (in X11) with

```
xrandr --output LVDS --set BACKLIGHT <value>
```

You can use "xrandr --prop" to see whether your X server can set your backlight, and what the range of acceptable values are; your output name may be different.  (note: you may need to emerge xrandr if you don't have it)

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## pappy_mcfae

 *Recruit0 wrote:*   

> I have Intel GM965. Yes I have a LCD display (laptop).
> 
> My screen doesn't appear to be blinking... At first I thought backlight support was needed because I didn't have a /sys/class/backlight directory but now I have one and there's nothing in it. I tried recompiling my kernel with backlight support but doesn't seem to do anything  
> 
> My brightness keys aren't working at all then. I tried xev with Fn + Up/Down and nothing comes up. Is there a way to do it manually? I was looking into editing some file but idk what file to edit... Stuff on google says to edit some file in the /sys/class/backlight directory but I don't have anything in there.

 

The fact that your /sys/class/backlight exists is enough reason for the Fn key dimming to stop working, AND it indicates what I originally said, that you have to disable lcd backlight support in the kernel. There are userspace options to work to dim or brighten the display, but they are, less than stellar at keeping the settings for how dim you want your display to be. 

Good luck.

Blessed be!

Pappy

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## Recruit0

I disabled backlight support in the kernel and that didn't do anything (the /sys/class/backlight is gone). The Fn + Up/Down still isn't being picked up by xev.

I'll try xrandr hopefully that works.

Edit: ^_^ It works. Max BACKLIGHT is 50001, current was 50000, changed to 25000. This won't damage my display or anything right? Just makin sure. Would be nice if my brightness keys worked... but this is fine.

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## pappy_mcfae

Glad you got it going.

Blessed be!

Pappy

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