On Fri, Sep 26, 2014 at 01:20:04PM +0100, Russell King - ARM Linux wrote:
> On Fri, Sep 26, 2014 at 07:25:01PM +0800, Chenhui Zhao wrote:
> > +static inline void ls1_do_lowpower(unsigned int cpu, int *spurious)
> > +{
> > + /*
> > + * there is no power-control hardware on this platform, so all
> > + * we can do is put the core into WFI; this is safe as the calling
> > + * code will have already disabled interrupts
> > + */
> > + for (;;) {
> > + wfi();
> > +
> > + if (pen_release == cpu_logical_map(cpu)) {
> > + /*OK, proper wakeup, we're done*/
> > + break;
> > + }
> > +
> > + /*
> > + * Getting here, means that we have come out of WFI without
> > + * having been woken up - this shouldn't happen
> > + *
> > + * Just note it happening - when we're woken, we can report
> > + * its occurrence.
> > + */
> > + (*spurious)++;
> > + }
> > +}
>
> This is pretty much unacceptable - this breaks kexec(), and suspend
> support because your secondary CPUs aren't really sleeping, they're
> sitting in a loop doing nothing.
Agreed.
This looks to be a carbon copy of the vexpress pseudo-hotplug in
arch/arm/mach-vexpress/hotplug.c, which is obviously broken in the way
you describe above. Perhaps we should go about ripping that out?
Mark.
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