linux-kernel - [Resend][PATCH] PCI / ACPI: Always resume devices on ACPI wakeup notifications

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Date:	Thu, 28 Mar 2013 18:10:34 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
Cc:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Len Brown <lenb@...nel.org>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Sarah Sharp <sarah.a.sharp@...ux.intel.com>,
	"Accardi, Kristen C" <kristen.c.accardi@...el.com>,
	"Huang, Ying" <ying.huang@...el.com>, linux-pci@...r.kernel.org
Subject: [Resend][PATCH] PCI / ACPI: Always resume devices on ACPI wakeup notifications

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

It turns out that the _Lxx control methods provided by some BIOSes
clear the PME Status bit of PCI devices they handle, which means that
pci_acpi_wake_dev() cannot really use that bit to check whether or
not the device has signalled wakeup.

The symptom of the problem is, for example, that when a PCI USB
controller is affected, then plugging in a new USB device into one of
the controller's ports will not wake up the controller, which should
happen.

For this reason, make pci_acpi_wake_dev() always attempt to resume
the device it is called for regardless of the device's PME Status bit
value (that bit still has to be cleared if set at this point,
though).

Reported-and-tested-by: Sarah Sharp <sarah.a.sharp@...ux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Acked-by: Matthew Garrett <mjg59@...f.ucam.org>
Cc: 3.7+ <stable@...r.kernel.org>
---
 drivers/pci/pci-acpi.c |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

Index: linux-pm/drivers/pci/pci-acpi.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-acpi.c
+++ linux-pm/drivers/pci/pci-acpi.c
@@ -53,14 +53,15 @@ static void pci_acpi_wake_dev(acpi_handl
 		return;
 	}
 
-	if (!pci_dev->pm_cap || !pci_dev->pme_support
-	     || pci_check_pme_status(pci_dev)) {
-		if (pci_dev->pme_poll)
-			pci_dev->pme_poll = false;
+	/* Clear PME Status if set. */
+	if (pci_dev->pme_support)
+		pci_check_pme_status(pci_dev);
 
-		pci_wakeup_event(pci_dev);
-		pm_runtime_resume(&pci_dev->dev);
-	}
+	if (pci_dev->pme_poll)
+		pci_dev->pme_poll = false;
+
+	pci_wakeup_event(pci_dev);
+	pm_runtime_resume(&pci_dev->dev);
 
 	if (pci_dev->subordinate)
 		pci_pme_wakeup_bus(pci_dev->subordinate);

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