linux-kernel - [PATCH 1/6] PM / Domains: Fix handling of wakeup devices during system resume

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Date:	Tue, 13 Mar 2012 01:24:11 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	"Linux-sh list" <linux-sh@...r.kernel.org>
Cc:	Linux PM list <linux-pm@...r.kernel.org>,
	Paul Mundt <lethal@...ux-sh.org>,
	Simon Horman <horms@...ge.net.au>,
	Magnus Damm <magnus.damm@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Cao Minh Hiep <hiepcm@...il.com>
Subject: [PATCH 1/6] PM / Domains: Fix handling of wakeup devices during system resume

From: Rafael J. Wysocki <rjw@...k.pl>

During system suspend pm_genpd_suspend_noirq() checks if the given
device is in a wakeup path (i.e. it appears to be needed for one or
more wakeup devices to work or is a wakeup device itself) and if it
needs to be "active" for wakeup to work.  If that is the case, the
function returns 0 without incrementing the device domain's counter
of suspended devices and without executing genpd_stop_dev() for the
device.  In consequence, the device is not stopped (e.g. its clock
isn't disabled) and power is always supplied to its domain in the
resulting system sleep state.

However, pm_genpd_resume_noirq() doesn't repeat that check and it
runs genpd_start_dev() and decrements the domain's counter of
suspended devices even for the wakeup device that weren't stopped by
pm_genpd_suspend_noirq().  As a result, the start callback may be run
unnecessarily for them and their domains' counters of suspended
devices may become negative.  Both outcomes aren't desirable, so fix
pm_genpd_resume_noirq() to look for wakeup devices that might not be
stopped by during system suspend.

Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
 drivers/base/power/domain.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: linux/drivers/base/power/domain.c
===================================================================
--- linux.orig/drivers/base/power/domain.c
+++ linux/drivers/base/power/domain.c
@@ -896,7 +896,8 @@ static int pm_genpd_resume_noirq(struct
 	if (IS_ERR(genpd))
 		return -EINVAL;

-	if (genpd->suspend_power_off)
+	if (genpd->suspend_power_off
+	    || (dev->power.wakeup_path && genpd_dev_active_wakeup(genpd, dev)))
 		return 0;

 	/*

--
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