>  
> +	/* we can receive multiple interrupts here, but the scheduled work
> +	 * will run only once, with the last value */
> +	pmac_backlight_key_queued = direction;

Shouldn't you be doing something like using the whole
pmac_backlight_key_queued in the workqueue, then setting it to 0 there
and using += here? That way all keypresses will be adhered to.

johannes