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    SubjectRe: [PATCH] ACPI: evaluate _PS3 when entering D3 Cold
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    On Monday, April 09, 2012, Lin Ming wrote:
    > On Mon, 2012-04-09 at 01:54 +0200, Rafael J. Wysocki wrote:
    > > 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?
    >
    > Yes.
    >
    > _PR0: {r1, r2, r3, r4, r5}
    > _PR3: {r4, r5}
    >
    > D0: {r1, r2, r3, r4, r5} are all on
    > D3 hot: {r1, r2, r3} are turned off and {r4, r5} are *left* on
    > D3 cold: {r1, r2, r3, r4, r5} are all turned off
    >
    > Is this correct?

    Yes, that's my understanding.

    > Thanks for your detail explanation.

    No problem.

    Thanks,
    Rafael


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