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PM / Runtime: Update documentation around probe|remove|suspend

PM core and driver core has changed some behavior regarding use of
runtime PM. Update the documentation accordingly.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Ulf Hansson 11 lat temu
rodzic
commit
ea309944e2
1 zmienionych plików z 6 dodań i 8 usunięć
  1. 6 8
      Documentation/power/runtime_pm.txt

+ 6 - 8
Documentation/power/runtime_pm.txt

@@ -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
 should be used.  Of course, for this purpose the device's runtime PM has to be
 enabled earlier by calling pm_runtime_enable().
 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
 Moreover, the driver core prevents runtime PM callbacks from racing with the bus
 notifier callback in __device_release_driver(), which is necessary, because the
 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
     __pm_runtime_disable() with 'false' as the second argument for every device
     right before executing the subsystem-level .suspend_late() callback for it.
     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()
     for every device right after executing the subsystem-level .resume_early()
     callback and right after executing the subsystem-level .resume() callback
     callback and right after executing the subsystem-level .resume() callback
     for it, respectively.
     for it, respectively.