Re: [PATCH] ACPI: Fix acpi_pm_device_sleep_state()

[Len Brown <lenb@kernel.org>]

> > BTW.  We currently don't use *d_min_p
> > and I can't imagine when and why we ever would,
> > so it would be fine with me if you simplify by deleting it.
> 
> It was requested by someone.  I can imagine that if _SxW > _SxD, a driver can
> decide which state to choose on the basis of some policy we don't know of.

I think that for the S3 and S4 states, we'll always use the deepest
state that the constraints allow while not breaking system wake.

I haven't thought much about "device wake" -- ie _PRW in S0.
Maybe some non-trivial device specific policy would be useful there
some day.  Of course the device would have to know the relative latency
of the different D-states for such a policy to make a useful.
And I guess they can infer that Dx state latency on a class basis...

-Len

> > Also, the last line of this block comment can be deleted,
> > though that was true before this patch also:
> 
> Not sure what you mean here ...
>  
> > acpi_pci_choose_state() block comment can now be updated to delete this line:
> > 
> > * currently we simply return _SxD, if present.
> 
> Yes, I'll do that in a separate patch.
> 
> Thanks,
> Rafael
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