Re: [PATCH] ACPI / scan: Always call acpi_bus_scan() for bus check notifications

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

On Mon, 2013-07-08 at 02:10 +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> An ACPI_NOTIFY_BUS_CHECK notification means that we should scan the
> entire namespace starting from the given handle even if the device
> represented by that handle is present (other devices below it may
> just have been added).
> 
> For this reason, modify acpi_scan_bus_device_check() to always run
> acpi_bus_scan() if the notification being handled is of type
> ACPI_NOTIFY_BUS_CHECK.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Cc: 3.10+ <stable@vger.kernel.org>

Acked-by: Toshi Kani <toshi.kani@hp.com>

But, I think we need the additional patch below.

Thanks,
-Toshi

=====
From: Toshi Kani <toshi.kani@hp.com>
Subject: [PATCH] ACPI: Do not call attach() if device is attached

attach() of ACPI scan handlers does not expect to be called multiple
times on a same device.  Also, the attached handler may not be changed
without calling its detach().  Change acpi_scan_attach_handler() not
to call attach() when the given device is already attached.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
---
 drivers/acpi/scan.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 20757e0..2b9e867 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1885,6 +1885,9 @@ static int acpi_scan_attach_handler(struct
acpi_device *device)
 	struct acpi_hardware_id *hwid;
 	int ret = 0;
 
+	if (device->handler)
+		return 1;
+
 	list_for_each_entry(hwid, &device->pnp.ids, list) {
 		const struct acpi_device_id *devid;
 		struct acpi_scan_handler *handler;