Re: [PATCH v3 4/5] ACPI / processor_idle : introduce ARCH_SUPPORTS_ACPI_PROCESSOR_CSTATE

From	"Rafael J. Wysocki" <rjw@rjwysocki.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 4/5] ACPI / processor_idle : introduce ARCH_SUPPORTS_ACPI_PROCESSOR_CSTATE
Date	2016-02-16 21:20 +0100
Message-ID	<r2Ugh-4i7-3@gated-at.bofh.it> (permalink)
References	<qBgqe-8gM-9@gated-at.bofh.it> <qBgqe-8gM-19@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wednesday, December 02, 2015 02:10:45 PM Sudeep Holla wrote:
> ACPI 6.0 adds a new method to specify the CPU idle states(C-states)
> called Low Power Idle(LPI) states. Since new architectures like ARM64
> use only LPIs, introduce ARCH_SUPPORTS_ACPI_PROCESSOR_CSTATE to
> encapsulate all the code supporting the old style C-states(_CST)

No.

The way it really should work is to check if the firmware supports LPI
(and what kind of it) and try to use _CST if LPI is not supported.

If LPI is supported by the firmware, use it if the LPI objects are
present as expected or fall back to using _CST otherwise.

This way it all should work without any new Kconfig options.

Thanks,
Rafael

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Re: [PATCH v3 4/5] ACPI / processor_idle : introduce ARCH_SUPPORTS_ACPI_PROCESSOR_CSTATE "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-02-16 21:20 +0100
  Re: [PATCH v3 4/5] ACPI / processor_idle : introduce  ARCH_SUPPORTS_ACPI_PROCESSOR_CSTATE Sudeep Holla <sudeep.holla@arm.com> - 2016-02-17 13:30 +0100
    Re: [PATCH v3 4/5] ACPI / processor_idle : introduce  ARCH_SUPPORTS_ACPI_PROCESSOR_CSTATE Sudeep Holla <sudeep.holla@arm.com> - 2016-02-22 14:50 +0100

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