Re: [PATCH v4 05/18] ARM64 / ACPI: Introduce sleep-arm.c

Jon Masters
2014-09-12T19:44:59Z

On 09/12/2014 10:00 AM, Hanjun Guo wrote:
> From: Graeme Gregory <graeme.gregory@linaro.org>
>
> ACPI 5.1 does not currently support S states for ARM64 hardware but
> ACPI code will call acpi_target_system_state() for device power
> managment, so introduce sleep-arm.c to allow other drivers to function
> until S states are defined.

Aside: ACPI5.1 does define the Platform Communication Channel and CPC
(Collaborative Processor Performance Control). Some details need to be
fleshed out there for practical 64-bit ARMv8 server systems, but the
underpinnings and mechanisms are in place in the 5.1 specification that
can be built upon over time to achieve practical S-State equivalence.

Jon.