# xbacklight doesn't work [solved]

## jerol

I can change the brightness manually by editing the text file in /sys/class/backlight/amdgpu_b10 but I can't use xbacklight to control it.

kernel config:

http://dpaste.com/4FD65YBJ7

lspci:

http://dpaste.com/734YQ7MJBLast edited by jerol on Sun Feb 20, 2022 10:31 pm; edited 1 time in total

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## alamahant

```

Note:

xbacklight only works with Intel. Other drivers (e.g. Radeon) did not add support for the RandR backlight property.

```

found in

https://wiki.archlinux.org/title/backlight#xbacklight

So plz keep echoing values to the file you mentioned.

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## jerol

Yeah I saw that, but that's weird because I used to change brightness just fine on void linux using xbacklight?

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## Hu

When did xbacklight work for you on Void Linux, and with what video card were you using it?

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## jerol

Like a week ago when I was still on void, the same machine. Though I figured that I need to install the sys-apps/acpilight instead of x11-apps/xbacklight.

They both have the same xbacklight binary, but now it seems that I can't use it without sudo.

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## Hu

If they have the same xbacklight binary, why does one work and the other not work?

What happens if you run it without sudo?  That you can get it to work with sudo suggests that it is just a wrapper around editing the /sys pseudo-file you mentioned earlier.

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## jerol

Thats a good question  :Very Happy: 

And it would just say no permission to the /sys file. Now though it works for some reason without evoking sudo :p I guess a reboot made it work.

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## grknight

 *jerol wrote:*   

> Like a week ago when I was still on void, the same machine. Though I figured that I need to install the sys-apps/acpilight instead of x11-apps/xbacklight.
> 
> They both have the same xbacklight binary, but now it seems that I can't use it without sudo.

 

They don't have the same binary, but acpilight's script, named xbacklight, provides compatible command line syntax to drop right in.

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