Re: [PATCH] implement pm_ops.valid for everybody

Pavel Machek
2007-03-24T00:01:47Z

Hi!

(I do not want to get into this flamewar).

> > That's a false choice, when you "mean" anything more than
> > fairly broad behavioral expectations: STR saves more power
> > than "standby", and transitions to/from STR take more
> > time than to/from "standby".
>
> So be it.
>
> Assume that the user does 'echo standby > /sys/power/state'. I think he can
> expect that in such a case we'll freeze tasks and put devices into low-power
> states and when he wakes up the system (BTW, I think the method of waking
> up can be treated as a differentiating factor) he should be able to continue
> from where he stopped after a little time. Fine.
>
> Now, we have to make that happen. After we have frozen tasks, we need to
> call something like device_suspend(some_argument) where the argument should
> tell drivers what to do. Say we use something like PMSG_STANDBY and now

We would add another field to that struct, distingushing "mem" and
"standby". And meaning for the drivers would be "try to save a lot of
power, but keep the latency low" for standby, vs. "save as much power
as possible" for mem.
Pavel
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