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

Rafael J. Wysocki
2012-04-01T07:25:01Z

On Sunday, April 01, 2012, Zhang Rui wrote:
[...]
>
> How about this?
>
> We should use the term "D3" in general in Linux.

I don't see why. We can refer to the "old D3" as D3_cold.

> Without _PR3, OS should *assume* that the power is removed, although it
> may be not true.

That's correct.

> With _PR3, OS can *assure* that the power is removed, because it knows
> how to remove thw power (evaluating _PR3._OFF).

I'd rather say that with _PR3 we have the opportunity to avoid removing
power completely from the device. In other words, D3_hot is supported (and
it is supported _only_ in that case).

> So the difference is that OS need to make sure whether to evaluate
> _PR3._OFF when _PR3 exists. For example, a device has _PR3, but _S0W
> returns 3, OS should not evaluate _PR3._OFF when the device sleeps with
> remote wakeup support.

That's correct.

> what do you think?

Well, see above and my other message in this thread.

Thanks,
Rafael