Laptop Panel brightness control

[Timo Hoenig]

On Mon, 2006-05-22 at 16:00 -0400, David Zeuthen wrote:

> I'm not sure it's important exactly _what_ generates the event (I think
> it's some input device created by kernel driver, maybe USB HID, Crispin
> can probably clarify here). 

It does matter.  This makes it difficult.

> Fact of the matter is that 
> 
>  1. we get an event when the brightness+ / brightness- key is pressed
>     so e.g. g-p-m can show some fancy bling graphics for that
> 
>  2. we know this is handled in hardware so e.g. g-p-m shouldn't attempt
>     to change the brightness
> 

Think of:

      * System with laptop_panel.brightness_in_hardware = true.
      * Fn-x keys on the laptop keyboard result in condition
        ButtonPressed = brightness-up;  no software intervention;  fine.
      * Press Brightness-Up on some other HID contected to this laptop
        results also in condition ButtonPressed = brightness-up;  no
        software intervention;  bad.

Now, identifying the source for the events does matter.

>     David

   Timo