Re: [Patch v1 1/3] ACPI: add callback prepare() into acpi_hotplug_handler

[Toshi Kani <toshi.kani@hp.com>]

On Sat, 2014-01-18 at 10:48 +0800, Jiang Liu wrote:
> Add callback prepare() into acpi_hotplug_handler, which will get called
> at the very beginning of ACPI hotplug event handler. The ACPI core will
> ignore the event if prepare() returns NOTIFY_STOP.
> 
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> ---
>  drivers/acpi/scan.c     |    4 ++++
>  include/acpi/acpi_bus.h |    1 +
>  2 files changed, 5 insertions(+)
> 
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index fd39459..6b0f419 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -392,6 +392,10 @@ static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data)
>  	struct acpi_device *adev;
>  	acpi_status status;
>  
> +	if (handler->prepare &&
> +	    handler->prepare(handle, type, data) == NOTIFY_STOP)
> +		return;

The OS is responsible for calling _OST when it is implemented.  So you
cannot just return here.  See acpi_hotplug_unsupported(handle, type)
next line.  Also, please describe why prepare() needs to be added.

Thanks,
-Toshi



> +
>  	if (!handler->hotplug.enabled)
>  		return acpi_hotplug_unsupported(handle, type);
>  
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index ddabed1..09a73bd 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -113,6 +113,7 @@ static inline struct acpi_hotplug_profile *to_acpi_hotplug_profile(
>  struct acpi_scan_handler {
>  	const struct acpi_device_id *ids;
>  	struct list_head list_node;
> +	int (*prepare)(acpi_handle handle, u32 type, void *context);
>  	int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);
>  	void (*detach)(struct acpi_device *dev);
>  	struct acpi_hotplug_profile hotplug;