Commit f8817f61 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PM / runtime: Drop children check from __pm_runtime_set_status() 



The check for "active" children in __pm_runtime_set_status(), when
trying to set the parent device status to "suspended", doesn't
really make sense, because in fact it is not invalid to set the
status of a device with runtime PM disabled to "suspended" in any
case.  It is invalid to enable runtime PM for a device with its
status set to "suspended" while its child_count reference counter
is nonzero, but the check in __pm_runtime_set_status() doesn't
really cover that situation.

For this reason, drop the children check from __pm_runtime_set_status()
and add a check against child_count reference counters of "suspended"
devices to pm_runtime_enable().

Fixes: a8636c89 (PM / Runtime: Don't allow to suspend a device with an active child)
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: default avatarJohan Hovold <johan@kernel.org>
parent bd2cd7d5

Documentation/power/runtime_pm.txt

+1 −2
Original line number Diff line number Diff line
@@ -435,8 +435,7 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: 
      PM status to 'suspended' and update its parent's counter of 'active'

      children as appropriate (it is only valid to use this function if

      'power.runtime_error' is set or 'power.disable_depth' is greater than

      zero); it will fail and return an error code if the device has a child

      which is active and the 'power.ignore_children' flag is unset

      zero)



  bool pm_runtime_active(struct device *dev);

    - return true if the device's runtime PM status is 'active' or its

drivers/base/power/runtime.c

+11 −20
Original line number Diff line number Diff line
@@ -1101,29 +1101,13 @@ int __pm_runtime_set_status(struct device *dev, unsigned int status) 
		goto out;

	}



	if (dev->power.runtime_status == status)

	if (dev->power.runtime_status == status || !parent)

		goto out_set;



	if (status == RPM_SUSPENDED) {

		/*

		 * It is invalid to suspend a device with an active child,

		 * unless it has been set to ignore its children.

		 */

		if (!dev->power.ignore_children &&

			atomic_read(&dev->power.child_count)) {

			dev_err(dev, "runtime PM trying to suspend device but active child\n");

			error = -EBUSY;

			goto out;

		}



		if (parent) {

		atomic_add_unless(&parent->power.child_count, -1, 0);

		notify_parent = !parent->power.ignore_children;

		}

		goto out_set;

	}



	if (parent) {

	} else {

		spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);



		/*
@@ -1307,6 +1291,13 @@ void pm_runtime_enable(struct device *dev) 
	else

		dev_warn(dev, "Unbalanced %s!\n", __func__);



	WARN(!dev->power.disable_depth &&

	     dev->power.runtime_status == RPM_SUSPENDED &&

	     !dev->power.ignore_children &&

	     atomic_read(&dev->power.child_count) > 0,

	     "Enabling runtime PM for inactive device (%s) with active children\n",

	     dev_name(dev));



	spin_unlock_irqrestore(&dev->power.lock, flags);

}

EXPORT_SYMBOL_GPL(pm_runtime_enable);

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