Re: [PATCH v6 00/25] PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM)

[Mark Rutland]

Hi Ulf,

On Wed, Mar 14, 2018 at 05:58:10PM +0100, Ulf Hansson wrote:
> For ARM, the PSCI firmware interface may be managing the power to the CPUs.
> Depending on the SoC, CPUs may also be arranged in hierarchical manner, which
> could add another level of complexity from a CPU idle management point of view.
> 
> PSCI v1.0+ adds support for the so called OS initiated CPU suspend mode, which
> enables a more fine grained method, allowing Linux to get more control, in
> regards to being energy efficient. This is typically useful for these kind of
> complex battery driven platforms.

> The series is based on v4.16-rc5, but applies also as of today to Rafael's
> linux-pm.git next branch. The code has been tested on a QCOM 410c dragonboard
> and I except that test coverage should be increased by some more boards
> shortly (for ARM64 with PSCI OSI support - only a few DT changes are needed).

Do we have any numbers to show how this affects energy efficiency?

Are there any other platforms with OSI support?

Thanks,
Mark.