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cpufreq: Revert commit a66b2e to fix suspend/resume regression

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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@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Srivatsa S. Bhat
2013-07-12 03:45:37 +05:30
committed by Greg Kroah-Hartman
parent 382b9efb7b
commit 9d3ce4af3b
2 changed files with 5 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/cpufreq/cpufreq.c
+3 -1
View File
@@ -1837,13 +1837,15 @@ static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
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;
}
drivers/cpufreq/cpufreq_stats.c
+2 -4
View File
@@ -353,13 +353,11 @@ static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
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;
}