From f8817f61e8215b0ff1b73a0d33fa04ef9e6bce8b Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 16 Nov 2017 22:51:22 +0100 Subject: [PATCH] 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: a8636c89648a (PM / Runtime: Don't allow to suspend a device with an active child) Signed-off-by: Rafael J. Wysocki Reviewed-by: Ulf Hansson Reviewed-by: Johan Hovold --- Documentation/power/runtime_pm.txt | 3 +-- drivers/base/power/runtime.c | 31 +++++++++++------------------- 2 files changed, 12 insertions(+), 22 deletions(-) diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 57af2f7963ee..937e33c46211 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -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 diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 2362b9e9701e..027d159ac381 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -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);