Messages in this thread | | | From | noman pouigt <> | Date | Wed, 11 Jul 2018 10:02:30 -0700 | Subject | Re: Re: devfreq relation with pm qos |
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On Mon, Jul 9, 2018 at 10:58 PM, MyungJoo Ham <myungjoo.ham@samsung.com> wrote: >> + dev freq maintainters. >> >> On Mon, Jul 9, 2018 at 3:37 AM, noman pouigt <variksla@gmail.com> wrote: >> > folks, >> > >> > I am trying to figure out the relationship between PM QOS >> > with devfreq framework. I see this thread[1] where MyungJoo >> > talks about QOS and devfreq but that control is through >> > sysfs but I don't see any relation of pm qos (kernel/power/qos.c) >> > with devfreq directly as devfreq is not calling any of the QOS >> > api's. Is this intended? >> > >> > Isn't QOS value update using pm_qos_update_request has a >> > direct relation with devfreq drivers i.e. setting the value to >> > high or low selects the corresponding voltage and frequency >> > setting in devfreq framework? I went through the devfreq >> > drivers and couldn't find that relationship. Is this by design or >> > I am missing something very obvious? >> > >> > [1] https://lwn.net/Articles/484161/ > > Hello, > > Unfortunately, the suggested concept in the referred article was not ever > accepted in the mainline.
MyungJo, I am trying to understand the relationship of PM QOS with devfreq drivers. I don't see any relation of PM QOS api's with devfreq drivers directly as there are no QOS apis used in the devfreq framework.
The only explanation I have is that PM QOS has direct relationship with CPUFREQ driver and as CPUFREQ driver works with CPU frequency and that CPU frequency directly affects DEVFREQ drivers as devfreq driver maps CPU frequency to device frequency and that is why PM QOS doesn’t have direct relation with PM QOS.
Is my understanding right?
> > Cheers, > MyungJo
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