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    SubjectRe: [PATCH] ACPI: evaluate _PS3 when entering D3 Cold
    Hi,

    On Sun, Apr 01, 2012 at 01:27:33PM +0800, Lin Ming wrote:
    > > - if (device->power.states[state].flags.explicit_set) {
    > > + /* If state is D3 Cold, try to evaluate _PS3 first */
    > > + if (state == ACPI_STATE_D3_COLD) {
    > > + explicit_set = (ps - 1)->flags.explicit_set;
    > > + object_name[3] -= 1;
    > > + }
    >
    > I'm not sure whether this works or not.
    >
    > From ACPI spec,
    >
    > _PS3 "is used to put the specific device into its D3hot or D3 state"
    >
    > D3 neither means D3hot nor D3cold. It's an old term before D3hot and
    > D3cold were introduced.
    I guess D3 has to mean something, right? :-)

    Here is the problem, there is no _PR3 in AMD's implementation, just _PS3.
    And since _S0W evaluates 4, I've to put this device into D3 cold state
    with _PS3.

    And the ACPI does have some words like:

    ------
    Platform/drivers must assume that the device will have power completely
    removed when the device is place into “D3” via _PS3
    ------

    This is in section 7.2.11: _PR3.

    >
    > Another problem:
    >
    > With your patch, both D3hot and D3cold will evaluate _PS3, right?
    >
    Yes.

    > Will it have problem on AMD platform if you try to put ODD into D3hot
    > state? _PS3 is evaluated, so it actually enters D3Cold state.

    There is no D3 hot support for this device(from the firmware's
    perspective), either it is at D0(via _PS0), or it will be at D3 cold(via
    _PS3).


    Thanks for the review.

    -Aaron

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