From: Johan Hovold <johan@kernel.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
Alan Stern <stern@rowland.harvard.edu>,
Kevin Hilman <khilman@baylibre.com>,
Tony Lindgren <tony@atomide.com>,
Ulf Hansson <ulf.hansson@linaro.org>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
Johan Hovold <johan@kernel.org>
Subject: [PATCH 1/2] PM / Runtime: fix autosuspend documentation
Date: Mon, 10 Apr 2017 13:38:24 +0200 [thread overview]
Message-ID: <20170410113825.17399-1-johan@kernel.org> (raw)
Update the autosuspend documentation which claimed that the autosuspend
delay is not taken into account when using the non-autosuspend helper
functions, something which is no longer true since commit d66e6db28df3
("PM / Runtime: Respect autosuspend when idle triggers suspend").
This specifically means that drivers must now disable autosuspend before
disabling runtime pm in probe error paths and remove callbacks if
pm_runtime_put_sync was being used to suspend the device before
returning. (If an idle callback can prevent suspend,
pm_runtime_put_sync_suspend must be used instead of pm_runtime_put_sync
as before.)
Also remove the claim that the autosuspend helpers behave "just like
the non-autosuspend counterparts", something which have never really
been true as some of the latter use idle notifications.
Signed-off-by: Johan Hovold <johan@kernel.org>
---
Documentation/power/runtime_pm.txt | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index 64546eb9a16a..56a13b865927 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -836,9 +836,8 @@ of the non-autosuspend counterparts:
Instead of: pm_runtime_put_sync use: pm_runtime_put_sync_autosuspend.
Drivers may also continue to use the non-autosuspend helper functions; they
-will behave normally, not taking the autosuspend delay into account.
-Similarly, if the power.use_autosuspend field isn't set then the autosuspend
-helper functions will behave just like the non-autosuspend counterparts.
+will behave normally, which means sometimes taking the autosuspend delay into
+account (see pm_runtime_idle).
Under some circumstances a driver or subsystem may want to prevent a device
from autosuspending immediately, even though the usage counter is zero and the
--
2.12.2
next reply other threads:[~2017-04-10 11:38 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-10 11:38 Johan Hovold [this message]
2017-04-10 11:38 ` [PATCH 2/2] PM / Runtime: document autosuspend-helper side effects Johan Hovold
2017-04-10 16:36 ` Tony Lindgren
2017-04-10 16:35 ` [PATCH 1/2] PM / Runtime: fix autosuspend documentation Tony Lindgren
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