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authorRafael J. Wysocki <rjw@sisk.pl>2011-06-21 23:47:15 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2011-06-21 23:47:15 +0200
commita5f76d5eba157bf637beb2dd18026db2917c512e (patch)
tree0f23e14459b8324e965c6a82d8b74dde1b4018e4 /drivers/pci
parentca9c6890b598997165a7c85c001f382c910f12b0 (diff)
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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 <rjw@sisk.pl> Cc: stable@kernel.org Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci-driver.c4
1 files changed, 3 insertions, 1 deletions
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 */