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Re: How to control LCD backlight via program?

On Wed, 24 Sep 2003 14:55:06 +0800 Yun-Ta Tsai wrote:
> Greeting,
> 	I plan to write a script to control my lcd backlight while entering power 
> saving mode.(Make it darker and after plugging in the AC power, it will 
> become brighter.) Is that possible to control the degree of the light of LCD? 
> I know someone wrote a program for Sony Vaio, is that possible do the same 
> stuff on ASUS laptop?

On my Asus L3C, running kernel 2.4.21 with ACPI patches, there's a file
somewhere under /proc/acpi/ that you can cat a value to (between 0 and 15,
I think), that will enable you to control the LCD backlight intensity.

Somewhere nearby there's also a file containing info on power mode (online
or battery).

I understand kernel 2.4.22 already has the latest ACPI patches included,
but I havent' tried it yet.

I prefer manual control, though. I have things set up so that, by pressing
the power mode button (leftmost of the top five), the relevant acpid
script toggles both processor modes and LCD backlight intensity levels, 
no matter what the power feed status is at the time.


Carlos Sousa

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