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    SubjectRe: [PATCH 2/2] cpufreq: don't call cpufreq_update_policy() on CPU addition
    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:
    >



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