Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751469AbcCLGCV (ORCPT ); Sat, 12 Mar 2016 01:02:21 -0500 Received: from mail.kernel.org ([198.145.29.136]:50410 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750799AbcCLGCL (ORCPT ); Sat, 12 Mar 2016 01:02:11 -0500 From: Krzysztof Kozlowski To: "Rafael J. Wysocki" , Len Brown , Pavel Machek , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Alan Stern , Krzysztof Kozlowski Subject: [PATCH] PM / runtime: Document steps for device removal Date: Sat, 12 Mar 2016 15:01:55 +0900 Message-Id: <1457762515-10295-1-git-send-email-krzk@kernel.org> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1894 Lines: 37 Put a reminder that during device removal drivers should revert all PM runtime changes from the probe. Also add a note that pm_runtime_disable() won't wait for pending suspend requests if autosuspend is not disabled before. Signed-off-by: Krzysztof Kozlowski --- Documentation/power/runtime_pm.txt | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 7328cf85236c..c05e5a17a52d 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -410,7 +410,8 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: field was previously zero, this prevents subsystem-level runtime PM callbacks from being run for the device), make sure that all of the pending runtime PM operations on the device are either completed or - canceled; returns 1 if there was a resume request pending and it was + canceled (although this depends on disabling autosuspend before + calling this); 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 @@ -586,6 +587,10 @@ 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