Messages in this thread | | | Date | Mon, 17 Feb 2014 14:24:43 +0530 | Subject | Re: [PATCH 2/2] cpufreq: don't call cpufreq_update_policy() on CPU addition | From | Viresh Kumar <> |
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On 17 February 2014 14:13, Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> wrote: > 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)..
Its not the wording that is wrong but this particular driver then :) This is what Documentation/cpu-drivers.txt says:
1.2 Per-CPU Initialization Then, the driver must fill in the following values:
policy->cur The current operating frequency of this CPU (if appropriate)
And so it is supposed to do it.
> 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 }
Its just about removing that from drivers and doing it once in core :)
>> 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>
Thanks.
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