From: Rafael J. Wysocki <[email protected]> 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(). Signed-off-by: Rafael J. Wysocki <[email protected]> --- drivers/base/power/runtime.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-) Index: linux-pm/drivers/base/power/runtime.c =================================================================== --- linux-pm.orig/drivers/base/power/runtime.c +++ linux-pm/drivers/base/power/runtime.c @@ -1101,29 +1101,13 @@ int __pm_runtime_set_status(struct devic 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 +1291,12 @@ void pm_runtime_enable(struct device *de else dev_warn(dev, "Unbalanced %s!\n", __func__); + WARN(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);
