Re: [patch V2 43/67] leds/trigger/cpu: Convert to hotplug state machine

[Jacek Anaszewski]

On 07/14/2016 01:33 PM, Thomas Gleixner wrote:
> On Thu, 14 Jul 2016, Jacek Anaszewski wrote:
> > On 07/14/2016 11:41 AM, Peter Zijlstra wrote:
> > > On Thu, Jul 14, 2016 at 10:10:55AM +0200, Jacek Anaszewski wrote:
> > > > On 07/14/2016 09:47 AM, Ingo Molnar wrote:
> > > > > * Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx> wrote:
> > > > >
> > > > > > > @@ -133,7 +125,13 @@ static int __init ledtrig_cpu_init(void)
> > > > > > >         }
> > > > > > >
> > > > > > >         register_syscore_ops(&ledtrig_cpu_syscore_ops);
> > > > > > > -     register_cpu_notifier(&ledtrig_cpu_nb);
> > > > > > > +
> > > > > > > +     /*
> > > > > > > +      * FIXME: Why needs this to happen in the interrupt disabled
> > > > > > > +      * low level bringup phase of a cpu?
> > > > > > > +      */
> > >
> > > > Thanks for the explanation. I'm OK with that approach.
> > >
> > > Since we have your attention, could you perhaps attempt to answer the
> > > question so we can fix the fixme?
> >
> > This is the way how all led triggers are being registered.
> >
> > Once a trigger module is loaded it needs to be registered in
> > the LED Trigger core.
>
> That does not explain WHY this needs to happen in the low level bringup phase
> of the CPU with interrupts disabled and can't be done from the normal ONLINE
> callbacks in thread context.

It was before my time in kernel, so I can only suppose that it was
the easiest way. Does it introduce some problems?

--
Best regards,
Jacek Anaszewski