Re: [PATCH v5 2/5] ACPI / processor_idle: Add support for Low Power Idle(LPI) states

From: Sudeep Holla
Date: Fri Jun 10 2016 - 13:38:11 EST


Hi Rafael,

On 11/05/16 16:37, Sudeep Holla wrote:
ACPI 6.0 introduced an optional object _LPI that provides an alternate
method to describe Low Power Idle states. It defines the local power
states for each node in a hierarchical processor topology. The OSPM can
use _LPI object to select a local power state for each level of processor
hierarchy in the system. They used to produce a composite power state
request that is presented to the platform by the OSPM.

Since multiple processors affect the idle state for any non-leaf hierarchy
node, coordination of idle state requests between the processors is
required. ACPI supports two different coordination schemes: Platform
coordinated and OS initiated.

This patch adds initial support for Platform coordination scheme of LPI.


I have added support for autopromote states(basically skip flattening or
creating composite state). I have also fixed the bug discussed in this
thread with Prashant. Do you have any other feedback on this version
that I incorporate before posting next version.

--
Regards,
Sudeep