linux-kernel - [PATCH] PM / suspend: Make cpuidle work in the "freeze" state

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Message-ID: <4271849.XeOTooWnSN@vostro.rjw.lan>
Date:	Sun, 20 Apr 2014 23:43:01 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Linux PM list <linux-pm@...r.kernel.org>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Zhang Rui <rui.zhang@...el.com>,
	Aubrey Li <aubrey.li@...el.com>,
	Preeti U Murthy <preeti@...ux.vnet.ibm.com>
Subject: [PATCH] PM / suspend: Make cpuidle work in the "freeze" state

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

The "freeze" system sleep state introduced by commit 7e73c5ae6e79
(PM: Introduce suspend state PM_SUSPEND_FREEZE) requires cpuidle
to be functional when freeze_enter() is executed to work correctly
(that is, to be able to save any more energy than runtime idle),
but that is impossible after commit 8651f97bd951d (PM / cpuidle:
System resume hang fix with cpuidle) which caused cpuidle to be
paused in dpm_suspend_noirq() and resumed in dpm_resume_noirq().

To avoid that problem, add cpuidle_resume() and cpuidle_pause()
to the beginning and the end of freeze_enter(), respectively.

Reported-by: Zhang Rui <rui.zhang@...el.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 kernel/power/suspend.c |    3 +++
 1 file changed, 3 insertions(+)

Index: linux-pm/kernel/power/suspend.c
===================================================================
--- linux-pm.orig/kernel/power/suspend.c
+++ linux-pm/kernel/power/suspend.c
@@ -14,6 +14,7 @@
 #include <linux/init.h>
 #include <linux/console.h>
 #include <linux/cpu.h>
+#include <linux/cpuidle.h>
 #include <linux/syscalls.h>
 #include <linux/gfp.h>
 #include <linux/io.h>
@@ -53,7 +54,9 @@ static void freeze_begin(void)

 static void freeze_enter(void)
 {
+	cpuidle_resume();
 	wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
+	cpuidle_pause();
 }

 void freeze_wake(void)

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