Messages in this thread | | | Date | Tue, 22 Mar 2016 09:00:32 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH 3/3] cpufreq: Always update current frequency before startig governor |
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On 21-03-16, 15:47, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > Make policy->cur match the current frequency returned by the driver's > ->get() callback before starting the governor in case they went out of > sync in the meantime and drop the piece of code attempting to > resync policy->cur with the real frequency of the boot CPU from > cpufreq_resume() as it serves no purpose any more (and it's racy and > super-ugly anyway). > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/cpufreq/cpufreq.c | 14 +++----------- > 1 file changed, 3 insertions(+), 11 deletions(-) > > Index: linux-pm/drivers/cpufreq/cpufreq.c > =================================================================== > --- linux-pm.orig/drivers/cpufreq/cpufreq.c > +++ linux-pm/drivers/cpufreq/cpufreq.c > @@ -1680,17 +1680,6 @@ void cpufreq_resume(void) > __func__, policy); > } > } > - > - /* > - * schedule call cpufreq_update_policy() for first-online CPU, as that > - * wouldn't be hotplugged-out on suspend. It will verify that the > - * current freq is in sync with what we believe it to be. > - */ > - policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask)); > - if (WARN_ON(!policy)) > - return; > - > - schedule_work(&policy->update); > } > > /** > @@ -2062,6 +2051,9 @@ static int cpufreq_start_governor(struct > { > int ret; > > + if (cpufreq_driver->get && !cpufreq_driver->setpolicy) > + cpufreq_update_current_freq(policy); > + > ret = cpufreq_governor(policy, CPUFREQ_GOV_START); > return ret ? ret : cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); > }
This looks fine, but I am searching for answers to few doubts, maybe you can help..
Why we did the same in process context earlier? And why it wouldn't be a problem now, when we do it in interrupt context? Will IRQs be disabled here? If so, then will you hit following ?
static void __cpufreq_notify_transition(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs, unsigned int state) { BUG_ON(irqs_disabled());
... }
And will calling notifiers from interrupt-context just fine ?
-- viresh
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