Re: [PATCH] ACPI: evaluate _PS3 when entering D3 Cold

[Rafael J. Wysocki]

On Thursday, April 05, 2012, Lin Ming wrote:
> On Thu, 2012-04-05 at 10:56 +0800, Aaron Lu wrote:
> > Hi,
> > 
> > On Thu, Apr 05, 2012 at 10:31:20AM +0800, Lin Ming wrote:
> > > > 
> > > > The only situation where a device can be put into ACPI D3_hot (which is not
> > > > the same as PCI D3_hot, mind you) is when:
> > > > 
> > > > (1) There is _PR3 listing some of the device's power resources as "on".
> > > > (2) The power resources listed by the _PR3 as "off" are turned off and the
> > > >     power resources listed by the _PR3 as "on" are left in the "on" state.
> > > 
> > > I don't understand item (2):
> > > 
> > > If the power resource is listed as "off", which means it's already
> > > turned off. Then why should it be turned off again?
> > 
> > Rafael,
> > I think you misunderstand the meaning of _PR3.
> > The _PR3 will evaluate a list of power resources, not two lists(one "on"
> > list and one "off" list), as illustrated by Ming below.
> > 
> > And for a device to be put to D3 hot, it should:
> > 1 execuate _PS3 first if available
> > 2 turn on all the power resources referenced by _PR3
> 
>   3 turn off all the power resources referenced by previous state

But leave the ones listed by _PR3 in the "on" state, you mean?

Rafael
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