Re: [PATCH] implement pm_ops.valid for everybody

Rafael J. Wysocki
2007-03-22T22:10:38Z

On Thursday, 22 March 2007 22:43, David Brownell wrote:
> On Thursday 22 March 2007 2:27 pm, Rafael J. Wysocki wrote:
> > On Thursday, 22 March 2007 19:29, David Brownell wrote:
> > >
> > > ... but I guess I don't see why one would want to try to nail down
> > > a definition of either "standby" or "STR".
> >
> > So that the meaning of "standby" and "STR" is known, more or less.
>
> But "more or less" != "nailed down (so tightly it's not always appicable)"
>
>
> > If you say "I'd like platforms to implement standby", you should say what
> > you mean by "standby", IMHO.
>
> I thought my original note described that, as well as describing how
> it differs from STR.
>
> STR shuts down a lot more. Not necessarily powering down the CPU
> (which is what would cause the need for boot/BIOS code to have the
> "this is really a resume" cases, and isn't always possible), but at
> least being more agressive about powering down clocks and such.

Well, I think the only clear distinction between the STR and "standby" is the
necessity to go through a boot-like procedure in order to resume from the
former. So, I'd tend to think the STR is when the CPU(s) is(are) powered
down and if some platforms don't support that, they just don't support the
STR.

Also, I'd like to define "standby" and STR as system-wide low power states
which involve the freezing of processes before entering them.

Greetings,
Rafael