Subject: Re: [RFC V2 PATCH 4/6] cpuidle/ppc: Add longnap state to the idle states on powernv

From: Preeti U Murthy <[email-masked]>
Date: Thu, 22 Aug 2013 14:39:20 +0530

Hi Ben,

On 08/22/2013 08:58 AM, Benjamin Herrenschmidt wrote:
> On Wed, 2013-08-14 at 17:26 +0530, Preeti U Murthy wrote:
>> This patch hooks into the existing broadcast framework along with the support
>> that this patchset introduces for ppc, and the cpuidle driver backend
>> for powernv(posted out by Deepthi Dharwar:https://lkml.org/lkml/2013/7/23/128)
>> to add sleep state as one of the deep idle states, in which the decrementer
>> is switched off.
>>
>> However in this patch, we only emulate sleep by going into a state which does
>> a nap with the decrementer interrupts disabled, termed as longnap. This enables
>> focus on the timer broadcast framework for ppc in this series of patches ,
>> which is required as a first step to enable sleep on ppc.
> 
> This is only for debug / proof of concept right ? We should use a real
> sleep here.
> 
> If we need to know whether the FW supports it (PORE etc...) we shall add
> a device-tree property from the FW to indicate that fact.

We also need the sleep support right? The context management, I mean.
Yes it is a debug patch, so as to first ensure that we have the hook up
to the broadcast framework done right.

Regards
Preeti U Murthy