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

Toshi Kani
2013-07-10T23:49:11Z

On Thu, 2013-07-11 at 00:45 +0200, Rafael J. Wysocki wrote:
> On Wednesday, July 10, 2013 02:11:05 AM Rafael J. Wysocki wrote:
> > On Tuesday, July 09, 2013 01:32:42 PM Toshi Kani wrote:
> > > 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.
> >
> > Yes, I think you're right.
>
> That said I'd prefer to put the check into acpi_bus_device_attach() like in
> the appended patch.

That's fine by me.

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

Just a minor point, though. Isn't it a bit inconsistent with
device_attach(), which checks dev->driver inside the function? That
said, I am OK with either way.

Thanks,
-Toshi

>
> Thanks,
> Rafael
>
>
> ---
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Subject: ACPI / scan: Do not try to attach scan handlers to devices having them
>
> In acpi_bus_device_attach(), if there is an ACPI device object
> for the given handle and that device object has a scan handler
> attached to it already, there's nothing more to do for that handle
> and the function should just return success immediately. Make
> that happen.
>
> Reported-by: Toshi Kani <toshi.kani@hp.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/acpi/scan.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -1984,6 +1984,9 @@ static acpi_status acpi_bus_device_attac
> if (acpi_bus_get_device(handle, &device))
> return AE_CTRL_DEPTH;
>
> + if (device->handler)
> + return AE_OK;
> +
> ret = acpi_scan_attach_handler(device);
> if (ret)
> return ret > 0 ? AE_OK : AE_CTRL_DEPTH;
>
> --
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