linux-kernel - [PATCH] PCI / ACPI / PM: Avoid resuming devices that don't signal PME

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Date:	Sun, 6 Nov 2011 22:21:46 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	ACPI Devel Mailing List <linux-acpi@...r.kernel.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Matthew Garrett <mjg59@...f.ucam.org>
Subject: [PATCH] PCI / ACPI / PM: Avoid resuming devices that don't signal PME

From: Rafael J. Wysocki <rjw@...k.pl>

Modify pci_acpi_wake_dev() to avoid resuming PME-capable devices
whose PME Status bits are not set, which may happen currently if
several devices are associated with the same wakeup GPE and all
of them are notified whenever at least one of them signals PME.

Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
 drivers/pci/pci-acpi.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

Index: linux/drivers/pci/pci-acpi.c
===================================================================
--- linux.orig/drivers/pci/pci-acpi.c
+++ linux/drivers/pci/pci-acpi.c
@@ -45,16 +45,20 @@ static void pci_acpi_wake_dev(acpi_handl
 {
 	struct pci_dev *pci_dev = context;
 
-	if (event == ACPI_NOTIFY_DEVICE_WAKE && pci_dev) {
+	if (event != ACPI_NOTIFY_DEVICE_WAKE || !pci_dev)
+		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;
 
 		pci_wakeup_event(pci_dev);
-		pci_check_pme_status(pci_dev);
 		pm_runtime_resume(&pci_dev->dev);
-		if (pci_dev->subordinate)
-			pci_pme_wakeup_bus(pci_dev->subordinate);
 	}
+
+	if (pci_dev->subordinate)
+		pci_pme_wakeup_bus(pci_dev->subordinate);
 }
 
 /**
--
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