linux-kernel - [ 021/103] cpufreq: Revert commit a66b2e to fix suspend/resume regression

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Message-Id: <20130723220420.939664935@linuxfoundation.org>
Date:	Tue, 23 Jul 2013 15:25:32 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org,
	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Paul Bolle <pebolle@...cali.nl>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [ 021/103] cpufreq: Revert commit a66b2e to fix suspend/resume regression

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>

commit aae760ed21cd690fe8a6db9f3a177ad55d7e12ab upstream.

commit a66b2e (cpufreq: Preserve sysfs files across suspend/resume)
has unfortunately caused several things in the cpufreq subsystem to
break subtly after a suspend/resume cycle.

The intention of that patch was to retain the file permissions of the
cpufreq related sysfs files across suspend/resume.  To achieve that,
the commit completely removed the calls to cpufreq_add_dev() and
__cpufreq_remove_dev() during suspend/resume transitions.  But the
problem is that those functions do 2 kinds of things:
  1. Low-level initialization/tear-down that are critical to the
     correct functioning of cpufreq-core.
  2. Kobject and sysfs related initialization/teardown.

Ideally we should have reorganized the code to cleanly separate these
two responsibilities, and skipped only the sysfs related parts during
suspend/resume.  Since we skipped the entire callbacks instead (which
also included some CPU and cpufreq-specific critical components),
cpufreq subsystem started behaving erratically after suspend/resume.

So revert the commit to fix the regression.  We'll revisit and address
the original goal of that commit separately, since it involves quite a
bit of careful code reorganization and appears to be non-trivial.

(While reverting the commit, note that another commit f51e1eb
 (cpufreq: Fix cpufreq regression after suspend/resume) already
 reverted part of the original set of changes.  So revert only the
 remaining ones).

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@...aro.org>
Tested-by: Paul Bolle <pebolle@...cali.nl>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/cpufreq/cpufreq.c       |    4 +++-
 drivers/cpufreq/cpufreq_stats.c |    6 ++----
 2 files changed, 5 insertions(+), 5 deletions(-)

--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1837,13 +1837,15 @@ static int __cpuinit cpufreq_cpu_callbac
 	if (dev) {
 		switch (action) {
 		case CPU_ONLINE:
+		case CPU_ONLINE_FROZEN:
 			cpufreq_add_dev(dev, NULL);
 			break;
 		case CPU_DOWN_PREPARE:
-		case CPU_UP_CANCELED_FROZEN:
+		case CPU_DOWN_PREPARE_FROZEN:
 			__cpufreq_remove_dev(dev, NULL);
 			break;
 		case CPU_DOWN_FAILED:
+		case CPU_DOWN_FAILED_FROZEN:
 			cpufreq_add_dev(dev, NULL);
 			break;
 		}
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -353,13 +353,11 @@ static int __cpuinit cpufreq_stat_cpu_ca
 		cpufreq_update_policy(cpu);
 		break;
 	case CPU_DOWN_PREPARE:
+	case CPU_DOWN_PREPARE_FROZEN:
 		cpufreq_stats_free_sysfs(cpu);
 		break;
 	case CPU_DEAD:
-		cpufreq_stats_free_table(cpu);
-		break;
-	case CPU_UP_CANCELED_FROZEN:
-		cpufreq_stats_free_sysfs(cpu);
+	case CPU_DEAD_FROZEN:
 		cpufreq_stats_free_table(cpu);
 		break;
 	}

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