iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

PM / runtime: Drop children check from __pm_runtime_set_status()

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

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' PM status to 'suspended' and update its parent's counter of 'active'
children as appropriate (it is only valid to use this function if children as appropriate (it is only valid to use this function if
'power.runtime_error' is set or 'power.disable_depth' is greater than '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 zero)
which is active and the 'power.ignore_children' flag is unset
bool pm_runtime_active(struct device *dev); bool pm_runtime_active(struct device *dev);
- return true if the device's runtime PM status is 'active' or its - return true if the device's runtime PM status is 'active' or its

27
drivers/base/power/runtime.c
View File

@ -1101,29 +1101,13 @@ int __pm_runtime_set_status(struct device *dev, unsigned int status)
goto out; goto out;
} }
if (dev->power.runtime_status == status) if (dev->power.runtime_status == status || !parent)
goto out_set; goto out_set;
if (status == RPM_SUSPENDED) { 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); atomic_add_unless(&parent->power.child_count, -1, 0);
notify_parent = !parent->power.ignore_children; notify_parent = !parent->power.ignore_children;
} } else {
goto out_set;
}
if (parent) {
spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING); spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
/* /*
@ -1307,6 +1291,13 @@ void pm_runtime_enable(struct device *dev)
else else
dev_warn(dev, "Unbalanced %s!\n", __func__); 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); spin_unlock_irqrestore(&dev->power.lock, flags);
} }
EXPORT_SYMBOL_GPL(pm_runtime_enable); EXPORT_SYMBOL_GPL(pm_runtime_enable);