Re: [PATCH 02/11] PM: extend PM QoS with per-device wake-up constraints

On Sunday, August 21, 2011, Mark Brown wrote:

On Sat, Aug 20, 2011 at 09:14:37PM +0200, Rafael J. Wysocki wrote:

quoted

I guess you mean the driver here and I'm not really sure it can.
For instance, the driver may not know what configuration it works in,
e.g. is there a power domain or a hierarchy of those and how much time
it takes to power them all down and up and what the power break even is.

I don't understand why the driver would need to know what situation it's
in.  I'd been working on the basis that the idea was that the driver
said what the constraints it has are and then some code with a more
system wide view would make the actual decisions for things outside the
driver domian.

That's correct, but in order to figure out a "sensible default"
the driver generally would need to know what the expectations with
respect to it are.  Otherwise it can very well generate a random
number and use that.

Thanks,
Rafael