On 02/17/2014 02:24 PM, Viresh Kumar wrote:
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.
Ah, I see.
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 :)
Ok..
Regards, Srivatsa S. Bhat