Messages in this thread | | | Date | Tue, 22 Mar 2016 20:12:08 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH 3/3] cpufreq: Always update current frequency before startig governor |
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On 22-03-16, 15:33, Rafael J. Wysocki wrote: > On Tuesday, March 22, 2016 09:00:32 AM Viresh Kumar wrote:
> > 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 ? > > I'm not sure I'm following.
Sorry about that.
> This is process context too. > > Look at the call sites of cpufreq_start_governor() (patch [1/3]): > - cpufreq_offline() - process context > - cpufreq_resume() - process context
I somehow thought that this is going to happen in interrupt context. :(
> - cpufreq_set_policy() - process context > - cpufreq_add_policy_cpu() - process context > > Besides, calling cpufreq_governor() from interrupt context wouldn't reall work, > because that acquires mutexes etc, like in cpufreq_governor_init(). > > > 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 ? > > If your question is why the original code doesn't call cpufreq_update_policy() > directly, I think the reason is because cpufreq_resume() used to be one of the > syscore ops and *that* would have been run in interrupt context.
Yeah.
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
-- viresh
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