Hi, On Sun, Apr 05, 2020 at 07:35:54PM +0200, Clément Péron wrote: > Now that required drivers are merged we can contibute on DVFS > support for Allwinner H6. > > This serie is based on Yangtao Li serie[0] and Ondřej Jirman work[1]. > > Most of the OPP tables are taken from original vendor kernel[2]. > Plus there is a new CPU frequencies at 1.6GHz, 1.7GHz and 1.8GHz. > > I wrote a simple script to randomly set a frequency during > a random time[3]. If you ever need to do that ever again, cpufreq-ljt-stress-test (found here https://github.com/ssvb/cpuburn-arm) has proven to be very reliable to detect cpufreq related issues. stress-ng might not be enough since the (at least older) Allwinner SoCs tend to create cache corruption when undervolted, and that might not be unnoticed by stress-ng but will be catched by cpufreq-ljt-stress-test. Also, it will test each frequency, while random frequencies might skip a few. > With this script and using stress-ng during several hours, I didn't > see any issue. Moreover I have tested specifically the 1.8GHz on my > Beelink GS1, max thermal 85°C is reached very quickly and then the > SoC oscillates quickly between 1.5 and 1.8GHz. So i have added > 1.6GHz and 1.7GHz my board now oscillate slower between 1.5GHz and > 1.6GHz swapping every second and temperature is also morestable. > > I also test that that offlining CPU0 and doing DVFS on other CPUs > works. As CPU regulator is only set for CPU0. > > But maybe it doesn't cost much to set the regulator for all the CPUs? > > Jernej test the GPU devfreq on several H6 board particulary the > Tanix TX6 which doesn't have a proper dedicated PMIC and doesn't > had any trouble with it. > > Do you think I can enable GPU OPP for all H6 Boards? It seems you're doing it? Maxime
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