diff options
| -rw-r--r-- | drivers/base/power/qos.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c index 71855570922..fd849a2c4fa 100644 --- a/drivers/base/power/qos.c +++ b/drivers/base/power/qos.c @@ -352,21 +352,26 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request); * * Will register the notifier into a notification chain that gets called * upon changes to the target value for the device. + * + * If the device's constraints object doesn't exist when this routine is called, + * it will be created (or error code will be returned if that fails). */ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier) { - int retval = 0; + int ret = 0; mutex_lock(&dev_pm_qos_mtx); - /* Silently return if the constraints object is not present. */ - if (dev->power.constraints) - retval = blocking_notifier_chain_register( - dev->power.constraints->notifiers, - notifier); + if (!dev->power.constraints) + ret = dev->power.power_state.event != PM_EVENT_INVALID ? + dev_pm_qos_constraints_allocate(dev) : -ENODEV; + + if (!ret) + ret = blocking_notifier_chain_register( + dev->power.constraints->notifiers, notifier); mutex_unlock(&dev_pm_qos_mtx); - return retval; + return ret; } EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier); |