On Thu, Nov 28, 2019 at 06:21:03PM +0100, Ulf Hansson wrote:
> On Thu, 28 Nov 2019 at 15:15, Lorenzo Pieralisi
> <lorenzo.pieralisi@xxxxxxx> wrote:
> >
> > On Wed, Nov 27, 2019 at 11:29:09AM +0100, Ulf Hansson wrote:
> >
> > [...]
> >
> > > +struct device *psci_dt_attach_cpu(int cpu)
> > > +{
> > > + struct device *dev;
> > > +
> > > + /* Currently limit the hierarchical topology to be used in OSI mode. */
> > > + if (!psci_has_osi_support())
> > > + return NULL;
> > > +
> > > + dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), "psci");
> > > + if (IS_ERR_OR_NULL(dev))
> > > + return dev;
> > > +
> > > + pm_runtime_irq_safe(dev);
> > > + if (cpu_online(cpu))
> >
> > It is unclear to me how we handle (or rather we don't) CPU hotplug
> > with this series - it does not look OK unless genpd code manages
> > that automatically.
>
> The series doesn't handle CPU hotplug at the moment, simply because I
> am targeting to get the basic support, upstream first.
Basic support must work and that includes CPU hotplug - I don't want
to merge code that work with assumptions that aren't valid.
> For a functionality point of view, this isn't a problem in my opinion.
> Simply because the consequence is only that the idle states for the
> "cluster" will not be reached if there is a CPU brought offline.
>
> As we talked about at LPC and as also told Sudeep for the v2 series,
> CPU hotplug is going to be implemented by using a CPU HP notifier.
Yes, it should be part of the series.
> That should be fine, right?
Yes, hopefully but it has to be part of the series.
Thanks,
Lorenzo
