[linux-pm] [PATCH v3 1/2] Input: enable i8042-level wakeup control

[Alan Stern]

On Thu, 28 Jul 2011, Daniel Drake wrote:

> The OLPC XO laptop is able to use the PS/2 controller as a wakeup source.
> When used as a wakeup source, the key press/mouse motion must not be lost.
> 
> Add infrastructure to allow controllers to be marked as wakeup-capable,
> and avoid doing power control/reset on the i8042/serio/input devices when
> running in this mode.
> 
> Signed-off-by: Daniel Drake <dsd at laptop.org>

> --- a/drivers/input/input.c
> +++ b/drivers/input/input.c
> @@ -1584,10 +1584,30 @@ void input_reset_device(struct input_dev *dev)
>  EXPORT_SYMBOL(input_reset_device);
>  
>  #ifdef CONFIG_PM
> +static bool input_may_wakeup(struct device *dev)
> +{
> +	/*
> +	 * Handle an i8042 wakeup corner case. The kernel sees the i8042 device
> +	 * and its grandchild input device as independent devices on different
> +	 * buses, so each one has its own suspend/resume implementation called
> +	 * from the PM layer.
> +	 *
> +	 * In this particular case, the wakeup enable setting on the
> +	 * grandparent i8042 device must take effect here, indicating that the
> +	 * input device is powered up and should not be touched during
> +	 * suspend/resume.
> +	 */
> +	return dev->parent && dev->parent->parent
> +		&& device_may_wakeup(dev->parent->parent);
> +}

Shouldn't this also check device_may_wakeup(dev)?  The user might 
disable wakeup for the input device while leaving it enabled for the 
i8042 device.

Alan Stern