linux-kernel - [PATCH 1/3] PCI / PM: Skip bridges in pci_enable

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Date:   Fri, 21 Jul 2017 14:38:08 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PCI <linux-pci@...r.kernel.org>
Cc:     Linux ACPI <linux-acpi@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Subject: [PATCH 1/3] PCI / PM: Skip bridges in pci_enable_wake()

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

PCI bridges only have a reason to generate wakeup signals on behalf
of devices below them, so avoid preparing bridges for wakeup directly
in pci_enable_wake().

Also drop the pci_has_subordinate() check from pci_pm_default_resume()
as this will be done by pci_enable_wake() itself now.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/pci/pci-driver.c |    4 +---
 drivers/pci/pci.c        |    7 +++++++
 2 files changed, 8 insertions(+), 3 deletions(-)

Index: linux-pm/drivers/pci/pci.c
===================================================================
--- linux-pm.orig/drivers/pci/pci.c
+++ linux-pm/drivers/pci/pci.c
@@ -1909,6 +1909,13 @@ int pci_enable_wake(struct pci_dev *dev,
 {
 	int ret = 0;
 
+	/*
+	 * Bridges can only signal wakeup on behalf of subordinate devices,
+	 * but that is set up elsewhere, so skip them.
+	 */
+	if (pci_has_subordinate(dev))
+		return 0;
+
 	/* Don't do the same thing twice in a row for one device. */
 	if (!!enable == !!dev->wakeup_prepared)
 		return 0;
Index: linux-pm/drivers/pci/pci-driver.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-driver.c
+++ linux-pm/drivers/pci/pci-driver.c
@@ -642,9 +642,7 @@ static int pci_legacy_resume(struct devi
 static void pci_pm_default_resume(struct pci_dev *pci_dev)
 {
 	pci_fixup_device(pci_fixup_resume, pci_dev);
-
-	if (!pci_has_subordinate(pci_dev))
-		pci_enable_wake(pci_dev, PCI_D0, false);
+	pci_enable_wake(pci_dev, PCI_D0, false);
 }
 
 static void pci_pm_default_suspend(struct pci_dev *pci_dev)