[3.11.y.z extended stable] Patch "PM / runtime: Use pm_runtime_put_sync() in __device_release_driver()" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    PM / runtime: Use pm_runtime_put_sync() in __device_release_driver()

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From ce2639e61a8bad3d3a934a8c213db15a0607e5c8 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki at intel.com>
Date: Thu, 7 Nov 2013 01:51:15 +0100
Subject: PM / runtime: Use pm_runtime_put_sync() in __device_release_driver()

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