[PATCH 2/2] ARM: iMX5 BBG: add cpuidle driver parameters

Yong Shen yong.shen at linaro.org
Wed Feb 9 04:40:07 EST 2011

On Tue, Feb 8, 2011 at 6:50 PM, Rob Herring <robherring2 at gmail.com> wrote:

> On 02/08/2011 09:51 AM, Yong Shen wrote:
>> Hi Arnaud,
>> I also took a while to think about this before posting patches. I prefer
>> to put it in board related code since the various PMIC used on each
>> boards may have influence on cpuidle latency or other charactors,
>> although it could be minor.
> But you are not going to be doing voltage scaling in idle. Is it even
> possible to do sleeping operations like accessing a PMIC in idle?
I guess you are asking if modes like 'state retention' are possible for idle
state. so far there is no official mapping between c-states and various arm
idle states, which is something linaro power management group is working on.
Therefore I also treat 'state retention' as a c-state.

ps. remove lpdk in cc list to avoid auto-reply messages.

> The core is powergated, so lowering voltage would not help. Doing bus
> scaling or DDR self-refresh are the only likely additional operations.
> Rob
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