[PATCH 3.11 128/272] PM / runtime: Use pm_runtime_put_sync() in __device_release_driver()

[Luis Henriques]

3.11.10.1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Rafael J. Wysocki" <rafael.j.wysocki at intel.com>

commit baab52ded242c35a2290e1fa82e0cc147d0d8c1a upstream.

Commit fa180eb448fa (PM / Runtime: Idle devices asynchronously after
probe|release) modified __device_release_driver() to call
pm_runtime_put(dev) instead of pm_runtime_put_sync(dev) before
detaching the driver from the device.  However, that was a mistake,
because pm_runtime_put(dev) causes rpm_idle() to be queued up and
the driver may be gone already when that function is executed.
That breaks the assumptions the drivers have the right to make
about the core's behavior on the basis of the existing documentation
and actually causes problems to happen, so revert that part of
commit fa180eb448fa and restore the previous behavior of
__device_release_driver().

Reported-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
Fixes: fa180eb448fa (PM / Runtime: Idle devices asynchronously after probe|release)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Acked-by: Kevin Hilman <khilman at linaro.org>
Acked-by: Ulf Hansson <ulf.hansson at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/base/dd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 35fa368..0605176 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -499,7 +499,7 @@ static void __device_release_driver(struct device *dev)
 						     BUS_NOTIFY_UNBIND_DRIVER,
 						     dev);
 
-		pm_runtime_put(dev);
+		pm_runtime_put_sync(dev);
 
 		if (dev->bus && dev->bus->remove)
 			dev->bus->remove(dev);
-- 
1.8.3.2