@@ -1725,15 +1725,18 @@ void cpufreq_resume(void)
|| __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
pr_err("%s: Failed to start governor for policy: %p\n",
__func__, policy);
-
- /*
- * schedule call cpufreq_update_policy() for boot CPU, i.e. last
- * policy in list. It will verify that the current freq is in
- * sync with what we believe it to be.
- */
- if (list_is_last(&policy->policy_list, &cpufreq_policy_list))
- schedule_work(&policy->update);
}
+
+ /*
+ * schedule call cpufreq_update_policy() for first-online CPU, as that
+ * wouldn't be hotplugged-out on suspend. It will verify that the
+ * current freq is in sync with what we believe it to be.
+ */
+ policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
+ if (WARN_ON(!policy))
+ return;
+
+ schedule_work(&policy->update);
}
/**
This is a note to let you know that I have just added a patch titled cpufreq: Schedule work for the first-online CPU on resume to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt11. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From e5fa3f26f924e55cb54d96714d41c5ffd55b5ace Mon Sep 17 00:00:00 2001 From: Viresh Kumar <viresh.kumar@linaro.org> Date: Thu, 2 Apr 2015 10:21:33 +0530 Subject: cpufreq: Schedule work for the first-online CPU on resume commit c75de0ac0756d4b442f460e10461720c7c2412c2 upstream. All CPUs leaving the first-online CPU are hotplugged out on suspend and and cpufreq core stops managing them. On resume, we need to call cpufreq_update_policy() for this CPU's policy to make sure its frequency is in sync with cpufreq's cached value, as it might have got updated by hardware during suspend/resume. The policies are always added to the top of the policy-list. So, in normal circumstances, CPU 0's policy will be the last one in the list. And so the code checks for the last policy. But there are cases where it will fail. Consider quad-core system, with policy-per core. If CPU0 is hotplugged out and added back again, the last policy will be on CPU1 :( To fix this in a proper way, always look for the policy of the first online CPU. That way we will be sure that we are calling cpufreq_update_policy() for the only CPU that wasn't hotplugged out. Fixes: 2f0aea936360 ("cpufreq: suspend governors on system suspend/hibernate") Reported-by: Saravana Kannan <skannan@codeaurora.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Saravana Kannan <skannan@codeaurora.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/cpufreq/cpufreq.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-)