From: Rafael J. Wysocki <rjw@xxxxxxx>
The runtime PM documentation in Documentation/power/runtime_pm.txt
doesn't say that pm_runtime_enable() and pm_runtime_disable() work by
operating on power.disable_depth, which is wrong, because the
possibility of nesting disables doesn't follow from the description
of these functions. Also, there is no description of
pm_runtime_barrier() at all in the document, which is confusing.
Improve the documentation by fixing those issues.
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
Documentation/power/runtime_pm.txt | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
Index: linux-2.6/Documentation/power/runtime_pm.txt
===================================================================
--- linux-2.6.orig/Documentation/power/runtime_pm.txt
+++ linux-2.6/Documentation/power/runtime_pm.txt
@@ -369,17 +369,27 @@ drivers/base/power/runtime.c and include
pm_runtime_autosuspend(dev) and return its result
void pm_runtime_enable(struct device *dev);
- - enable the run-time PM helper functions to run the device bus type's
- run-time PM callbacks described in Section 2
+ - decrement the device's 'power.disable_depth' field; if that field is equal
+ to zero, the run-time PM helper functions can execute subsystem-level
+ callbacks described in Section 2 for the device
int pm_runtime_disable(struct device *dev);
- - prevent the run-time PM helper functions from running subsystem-level
- run-time PM callbacks for the device, make sure that all of the pending
+ - increment the device's 'power.disable_depth' field (if the value of that
+ field was previously zero, this prevents subsystem-level runtime PM
+ callbacks from being run for the device), make sure that all of the pending
run-time PM operations on the device are either completed or canceled;
returns 1 if there was a resume request pending and it was necessary to
execute the subsystem-level resume callback for the device to satisfy that
request, otherwise 0 is returned
+ int pm_runtime_barrier(struct device *dev);
+ - check if there's a resume request pending for the device and resume it
+ (synchronously) in that case, cancel any other pending runtime PM requests
+ regarding it and wait for all runtime PM operations on it in progress to
+ complete; returns 1 if there was a resume request pending and it was
+ necessary to execute the subsystem-level resume callback for the device to
+ satisfy that request, otherwise 0 is returned
+
void pm_suspend_ignore_children(struct device *dev, bool enable);
- set/unset the power.ignore_children flag of the device
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