Re: [PATCH v2 5/9] PM / ACPI: Provide option to disable direct_complete for ACPI devices

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

On Friday, August 25, 2017 11:28:25 AM CEST Ulf Hansson wrote:
> [...]
> 
> >>
> >> The above change would offer an improvement, however there are more
> >> benefits from the runtime PM centric path that it doesn't cover.
> >
> > The idea, though, is not to make it instead of, but in addition to the
> > runtime PM centric path.
> >
> > So a driver using the runtime PM centric (or rather runtime PM aware)
> > callbacks can set power.force_suspend and benefit from having direct_complete
> > set conditional on whether or not the device is runtime resumed before the
> > late suspend.
> >
> > If device_complete remains set in __device_suspend_late(), no system
> > suspend/resume callbacks will be invoked from that point on.  If it isn't
> > set, pm_runtime_force_suspend() should work just fine and then
> > pm_runtime_force_resume() should do the right thing on the way back.
> >
> > All boils down to (a) setting a flag and (b) using the right callbacks
> > for system suspend which is the case with your patches either.
> 
> You make it sound simple. :-)
> 
> I try to get inspired of your ideas and see what I can come up with.
> However, I really want us to avoid making it more difficult to
> understand the behavior of the core, so I probably look start changing
> the ACPI PM domain first, then trying to adopt the behavior of the
> core on top of those changes. Does that sound reasonable to you?

Well, I don't think we need to change the ACPI PM domain at all. :-)

However, let me contiune in a reply to

https://marc.info/?l=linux-arm-kernel&m=150361200030186&w=2

for more complete context.

Thanks,
Rafael