linux-kernel - Re: [PATCH 1/16] ACPI: Separate adding ACPI device objects from probing ACPI drivers

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Date:	Fri, 11 Jan 2013 21:31:43 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Toshi Kani <toshi.kani@...com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	LKML <linux-kernel@...r.kernel.org>, linux-pci@...r.kernel.org,
	Yinghai Lu <yinghai@...nel.org>,
	Myron Stowe <myron.stowe@...hat.com>,
	Yijing Wang <wangyijing0307@...il.com>,
	Jiang Liu <liuj97@...il.com>
Subject: Re: [PATCH 1/16] ACPI: Separate adding ACPI device objects from probing ACPI drivers

On Friday, January 11, 2013 10:00:46 PM Mika Westerberg wrote:
> (Sorry to jump in late but I noticed one problem with this series while
> testing).
> 
> On Thu, Dec 20, 2012 at 02:47:47AM +0100, Rafael J. Wysocki wrote:
> > +static acpi_status acpi_bus_probe_start(acpi_handle handle, u32 lvl,
> > +					void *context, void **not_used)
> > +{
> > +	struct acpi_bus_ops *ops = context;
> > +	acpi_status status = AE_OK;
> > +	struct acpi_device *device;
> > +	unsigned long long sta_not_used;
> > +	int type_not_used;
> > +
> > +	/*
> > +	 * Ignore errors ignored by acpi_bus_check_add() to avoid terminating
> > +	 * namespace walks prematurely.
> > +	 */
> > +	if (acpi_bus_type_and_status(handle, &type_not_used, &sta_not_used))
> > +		return AE_OK;
> > +
> > +	if (acpi_bus_get_device(handle, &device))
> > +		return AE_CTRL_DEPTH;
> > +
> > +	if (ops->acpi_op_add) {
> > +		if (!acpi_match_device_ids(device, acpi_platform_device_ids)) {
> > +			/* This is a known good platform device. */
> > +			acpi_create_platform_device(device);
> > +		} else if (device_attach(&device->dev)) {
> 
> device_attach() returns 1 if it succeeds to attach device to a driver. In
> that case we should continue and not return AE_CTRL_DEPTH, right?

That's correct.  The check is reversed, so we need the appended patch on top
of linux-pm.git/acpi-scan.

Thanks,
Rafael


---
From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Subject: ACPI / scan: Fix check of device_attach() return value.

Since device_attach() returns 1 on success and 0 on failure,
the check against its return value in acpi_bus_device_attach()
should be reveresed.  Make it so.

Reported-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/acpi/scan.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -1598,7 +1598,7 @@ static acpi_status acpi_bus_device_attac
 	if (!acpi_match_device_ids(device, acpi_platform_device_ids)) {
 		/* This is a known good platform device. */
 		acpi_create_platform_device(device);
-	} else if (device_attach(&device->dev)) {
+	} else if (!device_attach(&device->dev)) {
 		status = AE_CTRL_DEPTH;
 	}
 	return status;

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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