# LCD backlight IOCTL

- List: linux-fbdev
- 2 messages, 2 authors
- Page: https://ratatoskr.run/linux-fbdev/2008/03/13458013/t

## LCD backlight IOCTL

- From: Rhee, C. Joon \<hidden\>
- Date: 2008-03-13 16:39:01 
- Message: https://ratatoskr.run/linux-fbdev/2008/03/13458013.md

```text
Hi, I'm searching for how we can specify the LCD backlight level through
/dev/fb.

And for this, should we introduce a new IOCTL?

 

FBIOGET/SET_BACKLIGHT

 

I looked through CONFIG_FB_BACKLIGHT and bl_dev registration but I found
this is more of internal usage when there is fb event and I don't really
see how user app can specify the level.

 

```

## Re: LCD backlight IOCTL

- From: Andres Salomon \<hidden\>
- Date: 2008-03-13 18:01:48 
- Message: https://ratatoskr.run/linux-fbdev/2008/03/13458014.md

```text
On Thu, 13 Mar 2008 09:38:51 -0700
"Rhee, C. Joon" [ref] wrote:

> Hi, I'm searching for how we can specify the LCD backlight level through
> /dev/fb.
> 
> And for this, should we introduce a new IOCTL?
> 
>  
> 
> FBIOGET/SET_BACKLIGHT
> 
>  
> 
> I looked through CONFIG_FB_BACKLIGHT and bl_dev registration but I found
> this is more of internal usage when there is fb event and I don't really
> see how user app can specify the level.
> 
>  
> 


backlight_device_register() takes a  struct backlight_ops that has
callbacks for getting and setting the backlight.  This ends up
being exported via sysfs, and is a nice way to adjust the backlight.

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```