From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754760Ab1FSTse (ORCPT ); Sun, 19 Jun 2011 15:48:34 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:40035 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754698Ab1FSTsb (ORCPT ); Sun, 19 Jun 2011 15:48:31 -0400 From: "Rafael J. Wysocki" To: Linux PM mailing list Subject: [PATCH] PCI / PM: Block races between runtime PM and system sleep Date: Sun, 19 Jun 2011 21:49:19 +0200 User-Agent: KMail/1.13.6 (Linux/3.0.0-rc3+; KDE/4.6.0; x86_64; ; ) Cc: LKML , Alan Stern , Jesse Barnes , "linux-pci@vger.kernel.org" MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201106192149.19401.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki After commit e8665002477f0278f84f898145b1f141ba26ee26 (PM: Allow pm_runtime_suspend() to succeed during system suspend) it is possible that a device resumed by the pm_runtime_resume(dev) in pci_pm_prepare() will be suspended immediately from a work item, timer function or otherwise, defeating the very purpose of calling pm_runtime_resume(dev) from there. To prevent that from happening it is necessary to increment the runtime PM usage counter of the device by replacing pm_runtime_resume() with pm_runtime_get_sync(). Moreover, the incremented runtime PM usage counter has to be decremented by the corresponding pci_pm_complete(), via pm_runtime_put_noidle(). Signed-off-by: Rafael J. Wysocki Cc: stable@kernel.org --- drivers/pci/pci-driver.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) Index: linux-2.6/drivers/pci/pci-driver.c =================================================================== --- linux-2.6.orig/drivers/pci/pci-driver.c +++ linux-2.6/drivers/pci/pci-driver.c @@ -624,7 +624,7 @@ static int pci_pm_prepare(struct device * system from the sleep state, we'll have to prevent it from signaling * wake-up. */ - pm_runtime_resume(dev); + pm_runtime_get_sync(dev); if (drv && drv->pm && drv->pm->prepare) error = drv->pm->prepare(dev); @@ -638,6 +638,8 @@ static void pci_pm_complete(struct devic if (drv && drv->pm && drv->pm->complete) drv->pm->complete(dev); + + pm_runtime_put_noidle(dev); } #else /* !CONFIG_PM_SLEEP */