Re: [PATCH 5/6] intel_idle: Add ->enter_freeze callbacks

Peter Zijlstra
2015-02-12T16:25:25Z

On Thu, Feb 12, 2015 at 05:24:51PM +0100, Rafael J. Wysocki wrote:
> On Thursday, February 12, 2015 02:26:43 PM Peter Zijlstra wrote:

> > Why bother with enter_freeze() for any but the deepest state (C6 in this
> > case)?
>
> User space may disable the deepest one (and any of them in general) via sysfs
> and there's no good reason to ignore its choice in this particular case while
> we're honoring it otherwise.
>
> So the logic is basically "find the deepest one which isn't disabled" and
> setting the pointers costs us nothing really.
>
> > Also, should we ignore things like intel_idle.max_cstate for this
> > selection?
>
> No, we shouldn't. The deeper ones may just not work then.

OK, fair enough.