| Date | Fri, 7 Jun 2019 16:31:14 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH 15/18] drivers: firmware: psci: Support CPU hotplug for the hierarchical model |
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On Mon, May 13, 2019 at 09:22:57PM +0200, Ulf Hansson wrote: > When the hierarchical CPU topology is used and when a CPU has been put > offline (hotplug), that same CPU prevents its PM domain and thus also > potential master PM domains, from being powered off. This is because genpd > observes the CPU's attached device as being active from a runtime PM point > of view. > > To deal with this, let's decrease the runtime PM usage count by calling > pm_runtime_put_sync_suspend() of the attached struct device when putting > the CPU offline. Consequentially, we must then increase the runtime PM > usage count, while putting the CPU online again. >
Why is this firmware/driver specific ? Why can't this be dealt in core pm-domain ? I am concerned that if any other architectures or firmware method decides to use this feature, this need to be duplicated there.
The way I see this is pure reference counting and is hardware/firmware/ driver agnostic and can be made generic.
-- Regards, Sudeep
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