From a5f76d5eba157bf637beb2dd18026db2917c512e Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 21 Jun 2011 23:47:15 +0200 Subject: [PATCH] PCI / PM: Block races between runtime PM and system sleep 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_sync(). Signed-off-by: Rafael J. Wysocki Cc: stable@kernel.org Acked-by: Jesse Barnes --- drivers/pci/pci-driver.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 135df16..46767c5 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -624,7 +624,7 @@ static int pci_pm_prepare(struct device *dev) * 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 device *dev) if (drv && drv->pm && drv->pm->complete) drv->pm->complete(dev); + + pm_runtime_put_sync(dev); } #else /* !CONFIG_PM_SLEEP */ -- 2.7.4