On Mon, Nov 21, 2022 at 11:57:30AM -0800, Wing Li wrote:
+Ulf Hansson ulf.hansson@linaro.org and +Jens Wiklander jens.wiklander@linaro.org, who are able to help with testing.
Hi Sudeep and Jacky,
I wanted to clarify our use case for suspend-to-idle. For mobile and other battery-powered devices, the key capability we need isn't just the ability to enter s2idle, but also reaching equivalent power savings in s2idle compared to suspend-to-RAM. Essentially, if all CPU cores are idle, we want to be able to drop into the deepest low-power state that is just as energy-efficient as suspend-to-RAM, but without hot-unplugging and plugging the CPUs, which means they need to be able to resume in their idle loops. To achieve this, we're planning to leverage the hierarchical power domain representation in the device tree [1], which is currently limited to be used in OS-initiated mode by the PSCI CPUIdle driver [2].
OK, so your choice is OSI and it has nothing to do with S2I not working with PC mode cpuidle. The statement that Linux S2I requires OSI mode of cpuidle was misleading and main trigger for most of these discussions.