[PATCH v8 0/6] ACPI / processor_idle: Add ACPI v6.0 LPI support
Sudeep Holla
sudeep.holla at arm.com
Fri Jul 8 08:19:25 PDT 2016
On 08/07/16 15:43, Lorenzo Pieralisi wrote:
> On Fri, Jul 08, 2016 at 12:04:40PM +0100, Sudeep Holla wrote:
>>
>>
>> On 07/07/16 22:02, Rafael J. Wysocki wrote:
>>> On Thu, Jul 7, 2016 at 7:10 PM, Sudeep Holla <sudeep.holla at arm.com> wrote:
>>>> ACPI 6.0 introduced LPI(Low Power Idle) states that provides an alternate
>>>> method to describe processor idle states. It extends the specification
>>>> to allow the expression of idle states like C-states selectable by the
>>>> OSPM when a processor goes idle, but may affect more than one processor,
>>>> and may affect other system components.
>>>>
>>>> LPI extensions leverages the processor container device(again introduced
>>>> in ACPI 6.0) allowing to express which parts of the system are affected
>>>> by a given LPI state. 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 series aims at providing basic and initial support for platform
>>>> coordinated LPI states.
>>>>
>>>> v7[7]->v8:
>>>> - Replaced HAVE_GENERIC_CPUIDLE_ENTER with CPU_IDLE_ENTER_WRAPPED
>>>> macro, which is more cleaner and definately less confusing :)
>>>> (Thanks to Rafael for the suggestion)
>>>
>>> Patches [3-6/6] definitely look a lot cleaner to me now. :-)
>>>
>>> That said, the name of the macro I suggested was just an example, so
>>> if people don't like this one, it'd be fine to change it as far as I'm
>>> concerned.
>>>
>>
>> I can think of addition to indicate it's pm notifiers wrapper.
>> i.e. CPU_IDLE_ENTER_PM_NOTIFIERS_WRAPPED. Is it too long ? I am happy
>> with the way it is too.
>
> CPU_PM_CPU_IDLE_ENTER() ? Anyway, that's really not a problem IMO,
> it makes sense to at least mention CPU PM in it given that's what
> the CPUIDLE enter function is wrapped within.
>
Looks even better IMO, Rafael if you have no objection, I will change to
CPU_PM_CPU_IDLE_ENTER ?
--
Regards,
Sudeep
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