[PATCH v2] PM / runtime: Document steps for device removal

Krzysztof Kozlowski
2016-04-03T03:23:31Z

Put a reminder that during device removal drivers should revert all PM
runtime changes from the probe.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

---

Changes since v1:
1. Address Alan's comments.
---
Documentation/power/runtime_pm.txt | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index 7328cf85236c..1fd1fbe9ce95 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -586,6 +586,10 @@ drivers to make their ->remove() callbacks avoid races with runtime PM directly,
but also it allows of more flexibility in the handling of devices during the
removal of their drivers.

+Drivers in ->remove() callback should undo the runtime PM changes done
+in ->probe(). Usually this means calling pm_runtime_disable(),
+pm_runtime_dont_use_autosuspend() etc.
+
The user space can effectively disallow the driver of the device to power manage
it at run time by changing the value of its /sys/devices/.../power/control
attribute to "on", which causes pm_runtime_forbid() to be called. In principle,
--
2.1.4