On 24/03/2021 04:51, Samuel Holland wrote: > On 3/22/21 9:18 AM, Daniel Lezcano wrote: >> On 22/03/2021 05:47, Samuel Holland wrote: >>> In preparation for adding CPU idle states, hook up the sun4i timer. >>> Having a non-c3stop clockevent source available is necessary for all >>> CPUs to simultaneously enter a local-timer-stop idle state. >> >> Why simultaneously ? > Because the CPU providing (the hrtimer providing) the broadcast timer > cannot enter an idle state which would stop that timer. So in my case, > with 4 CPUs, I was seeing at most 3 CPUs enter idle at any given time. > This prevented any cluster-level idle states from doing anything. After > applying this series, I was able to observe the whole cluster powering > down when appropriate.
Ah, ok. I did not realize this fourth CPU was acting as the broadcast timer, so allowing at least a CPU power down. This setup is unusual. The changes make sense. Acked-by: Daniel Lezcano <daniel.lezc...@linaro.org> -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
