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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2012-12-22 23:59:01 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-01-06 00:35:55 +0100
commit9f6d8f6ab26b42620a914d67f29822f9bba90233 (patch)
treeac243fb6970bf2b870e34e061281f7ad5446ad38 /Documentation/power
parentd1c3ed669a2d452cacfb48c2d171a1f364dae2ed (diff)
downloadlinux-9f6d8f6ab26b42620a914d67f29822f9bba90233.tar.gz
PM: Move disabling/enabling runtime PM to late suspend/early resume
Currently, the PM core disables runtime PM for all devices right after executing subsystem/driver .suspend() callbacks for them and re-enables it right before executing subsystem/driver .resume() callbacks for them. This may lead to problems when there are two devices such that the .suspend() callback executed for one of them depends on runtime PM working for the other. In that case, if runtime PM has already been disabled for the second device, the first one's .suspend() won't work correctly (and analogously for resume). To make those issues go away, make the PM core disable runtime PM for devices right before executing subsystem/driver .suspend_late() callbacks for them and enable runtime PM for them right after executing subsystem/driver .resume_early() callbacks for them. This way the potential conflitcs between .suspend_late()/.resume_early() and their runtime PM counterparts are still prevented from happening, but the subtle ordering issues related to disabling/enabling runtime PM for devices during system suspend/resume are much easier to avoid. Reported-and-tested-by: Jan-Matthias Braun <jan_braun@gmx.net> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: 3.4+ <stable@vger.kernel.org>
Diffstat (limited to 'Documentation/power')
-rw-r--r--Documentation/power/runtime_pm.txt9
1 files changed, 5 insertions, 4 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index 4abe83e1045..03591a750f9 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -642,12 +642,13 @@ out the following operations:
* During system suspend it calls pm_runtime_get_noresume() and
pm_runtime_barrier() for every device right before executing the
subsystem-level .suspend() callback for it. In addition to that it calls
- pm_runtime_disable() for every device right after executing the
- subsystem-level .suspend() callback for it.
+ __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()
- for every device right before and right after executing the subsystem-level
- .resume() callback for it, respectively.
+ for every device right after executing the subsystem-level .resume_early()
+ callback and right after executing the subsystem-level .resume() callback
+ for it, respectively.
7. Generic subsystem callbacks