On 02/14/2014 04:30 PM, Viresh Kumar wrote:
cpufreq_update_policy() is called from two places currently. From a workqueue handled queued from cpufreq_bp_resume() for boot CPU and from cpufreq_cpu_callback() whenever a CPU is added.
The first one makes sure that boot CPU is running on the frequency present in policy->cpu. But we don't really need a call from cpufreq_cpu_callback(), because we always call cpufreq_driver->init() (which will set policy->cur correctly) whenever first CPU of any policy is added back. And so every policy structure is guaranteed to have the right frequency in policy->cur.
This wording is slightly inaccurate. ->init() may or may not set policy->cur (for example, powernowk8 driver doesn't set it in the init routine).. But we set it for sure in __cpufreq_add_dev():
1117 if (cpufreq_driver->get) { 1118 policy->cur = cpufreq_driver->get(policy->cpu); 1119 if (!policy->cur) { 1120 pr_err("%s: ->get() failed\n", __func__); 1121 goto err_get_freq; 1122 } 1123 }
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
The reasoning and the code looks good to me.
Reviewed-by: Srivatsa S. Bhat srivatsa.bhat@linux.vnet.ibm.com
Regards, Srivatsa S. Bhat
drivers/cpufreq/cpufreq.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 383362b..b6eb4ed 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2194,7 +2194,6 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, switch (action & ~CPU_TASKS_FROZEN) { case CPU_ONLINE: __cpufreq_add_dev(dev, NULL, frozen);
cpufreq_update_policy(cpu); break;case CPU_DOWN_PREPARE: