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Merge branch 'pm-runtime'

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* pm-runtime:
  PM / Runtime: Fix error path for prepare
  PM / Runtime: Update documentation around probe|remove|suspend
This commit is contained in:
Rafael J. Wysocki 2013-11-19 01:06:49 +01:00
commit 77aa26514a
2 changed files with 9 additions and 8 deletions
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14
Documentation/power/runtime_pm.txt
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@ -547,13 +547,11 @@ helper functions described in Section 4. In that case, pm_runtime_resume()
should be used. Of course, for this purpose the device's runtime PM has to be
enabled earlier by calling pm_runtime_enable().
If the device bus type's or driver's ->probe() callback runs
pm_runtime_suspend() or pm_runtime_idle() or their asynchronous counterparts,
they will fail returning -EAGAIN, because the device's usage counter is
incremented by the driver core before executing ->probe(). Still, it may be
desirable to suspend the device as soon as ->probe() has finished, so the driver
core uses pm_runtime_put_sync() to invoke the subsystem-level idle callback for
the device at that time.
It may be desirable to suspend the device once ->probe() has finished.
Therefore the driver core uses the asyncronous pm_request_idle() to submit a
request to execute the subsystem-level idle callback for the device at that
time. A driver that makes use of the runtime autosuspend feature, may want to
update the last busy mark before returning from ->probe().
Moreover, the driver core prevents runtime PM callbacks from racing with the bus
notifier callback in __device_release_driver(), which is necessary, because the
@ -656,7 +654,7 @@ out the following operations:
__pm_runtime_disable() with 'false' as the second argument for every device
right before executing the subsystem-level .suspend_late() callback for it.
* During system resume it calls pm_runtime_enable() and pm_runtime_put_sync()
* During system resume it calls pm_runtime_enable() and pm_runtime_put()
for every device right after executing the subsystem-level .resume_early()
callback and right after executing the subsystem-level .resume() callback
for it, respectively.

3
drivers/base/power/main.c
View File

@ -1350,6 +1350,9 @@ static int device_prepare(struct device *dev, pm_message_t state)
device_unlock(dev);
if (error)
pm_runtime_put(dev);
return error;
}