Messages in this thread | | | Date | Thu, 3 Feb 2022 11:14:35 +0000 | From | Sudeep Holla <> | Subject | Re: [PATCH 0/4] Broadcom STB PM PSCI extensions |
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On Fri, Jan 21, 2022 at 07:54:17PM -0800, Florian Fainelli wrote: > Hi all, > > This patch series contains the Broadcom STB PSCI extensions which adds > some additional functions on top of the existing standard PSCI interface > which is the reason for having the driver implement a custom > suspend_ops. > > These platforms have traditionally supported a mode that is akin to > ACPI's S2 with the CPU in WFI and all of the chip being clock gated > which is entered with "echo standby > /sys/power/state". Additional a > true suspend to DRAM as defined in ACPI by S3 is implemented with "echo > mem > /sys/power/state".
How different is the above "standby" state compare to the standard "idle" (a.k.a suspend-to-idle which is different from system-to-ram/S3) ? Suspend to idle takes all the CPUs to lowest possible power state instead of cpu-hotplug in S2R. Also I assume some userspace has to identify when to enter "standby" vs "mem" right ? I am trying to see how addition of "idle" changes that(if it does). Sorry for too many questions.
-- Regards, Sudeep
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