Messages in this thread | | | From | Amit Kucheria <> | Date | Thu, 8 Mar 2018 11:05:55 +0530 | Subject | Re: [PATCH] thermal: of: Allow selection of thermal governor in DT |
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On Thu, Mar 8, 2018 at 10:19 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote: > On Wed, Mar 7, 2018 at 4:29 PM, Amit Kucheria <amit.kucheria@linaro.org> wrote: >> Cpufreq/cpuidle are designed to control a single parameter while >> thermal framework is trying to mitigate heat from several disparate >> sources that are throttled in different ways. Besides, cpufreq/cpuidle >> have somewhat mature governors. Cpuidle has only one governor (for >> tickless) - menu governor, cpufreq has ondemand in mainline, replaced >> by interactive in android and hopefully soon both will be replaced by > > Interactive and schedfreq are already removed from Android 4.4 and 4.9. > It used schedutil now.
Good to hear.
>> schedutil. >> >> Badly configured cpufreq/cpuidle/devfreq only leads to wasted power, >> while badly configured thermal zone leads to the loss of operation >> e.g. reboots, too hot to touch, etc. > > I don't think such heat-ups will happen right during boot, where some > init.rc should > come up and change the governor.
Interestingly enough, there are some patches that make the thermal framework start earlier to deal with boot-time thermal issues. I expect to post them soon. :-) These are required, for example, if the device goes into a reboot loop - the device might not even make it to the point in userspace where the governors are setup. In such a loop, the temperature constantly keeps increasing.
> Over that if we are worried about production images only, then what prevents us > to select the right default governor in the defconfig ? We shouldn't > be worried about > multi-platform kernels for production images.
I was refering to the 'make defconfig' out-of-box experience that makes the majority of developer boards/devices out there stable to work on. I can't do that today.
Regards, Amit
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