Messages in this thread | | | Date | Thu, 21 Nov 2013 21:47:20 +0530 | Subject | Re: [PATCH] cpufreq: suspend/resume governors with PM notifiers | From | Viresh Kumar <> |
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On 21 November 2013 20:08, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > On Wednesday, November 20, 2013 11:04:28 AM Viresh Kumar wrote: >> On 18 November 2013 11:09, viresh kumar <viresh.kumar@linaro.org> wrote:
>> > Because in our usecase, we just want to know when suspend has started or >> > resume has finished. And so we really don't need a per cpu callback. > > But it won't hurt I suppose?
Hmm.. getting a single call to cpufreq core would be faster for sure. Otherwise we need to mark all the calls leaving the first one as no-ops..
> That actually isn't correct. On systems with ACPI the processor driver binds to > those devices. So the processor driver could use PM callbacks on those systems > in principle.
> Introduce proper drivers for processors? All of the cpuidle and cpufreq stuff > currently works by using its own homegrown device registration methods etc, but > surely that doesn't have to be the case?
Hmm.. So you are asking for a new cpu-driver which can be used by cpufreq and cpuidle to get callback? If yes, where such driver will exist? And will the ACPI processor-drivers exist parallely? Or something else?
>> > And I really feel even if we would be able to use cpu callbacks for >> > suspend/resume, that would be a real *Hack*, because our framework doesn't want >> > to get a callback for each of its devices (i.e. cpu) but a single callback at >> > certain instances.. > > Oh really? So CPUs are not individual devices any more or what?
I am not calling cpu callbacks as hack but using them for cpufreq looked like one to me.
Replying here to the other mail as well:
On 21 November 2013 20:09, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > On Monday, November 18, 2013 09:37:39 PM Lan Tianyu wrote: >> Another point, I just see cpuidle_resume() and cpuidle_pause() are >> called in the dpm_resume_noirq and dpm_suspend_noirq(). Not sure whether >> this can be applied to cpufreq. > > I don't see why not.
Interesting. So you would be happy if I add such calls after freezing userspace and before restoring it back for cpufreq?
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