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Subject[PATCH 1/8] cpufreq: Revert commit a66b2e to fix cpufreq regression during suspend/resume
Date
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).

Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---

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

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 6a015ad..ccc6eab 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1941,13 +1941,15 @@ 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;
}
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index cd9e817..12225d1 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -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;
}


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