| Message ID | 8f2fc4d6240b567fdb69a0b47f073d174b7ef9b2.1392375504.git.viresh.kumar@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 17 February 2014 05:51, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > On Friday, February 14, 2014 04:30:41 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. > > That sounds good, but doing the extra cpufreq_update_policy() shouldn't actually > hurt, should it? Yeah, it shouldn't hurt badly.. > So, that would be a cleanup rather than a fix, right? Hmm, yeah.. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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:
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. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/cpufreq/cpufreq.c | 1 - 1 file changed, 1 deletion(-)