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PM / runtime: Drop children check from __pm_runtime_set_status()

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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: a8636c8964 (PM / Runtime: Don't allow to suspend a device with an active child)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Rafael J. Wysocki 2017-11-16 22:51:22 +01:00
parent bd2cd7d5a8
commit f8817f61e8
2 changed files with 12 additions and 22 deletions
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3
Documentation/power/runtime_pm.txt
View File

@ -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

31
drivers/base/power/runtime.c
View File

@ -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) {
atomic_add_unless(&parent->power.child_count, -1, 0);
notify_parent = !parent->power.ignore_children;
} 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);