Messages in this thread | | | Subject | Re: [PATCH] ACPI: evaluate _PS3 when entering D3 Cold | From | Lin Ming <> | Date | Mon, 09 Apr 2012 09:38:45 +0800 |
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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?
Thanks for your detail explanation.
> > Rafael
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