[Skiboot] [PATCH] hw/slw.c: Offline code still uses p8 bits

[Vaidyanathan Srinivasan]

* Stewart Smith <stewart at linux.vnet.ibm.com> [2017-09-15 18:17:46]:

> Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com> writes:
> > * Balbir Singh <bsingharora at gmail.com> [2017-09-15 14:42:39]:
> >
> >> I'm seeing an infinite loop while hot unplugging
> >> a CPU. This is a workaround till we do the right
> >> things for p9. May be a candidate for backporting
> >> 
> >> The messages I see in an infinite loop are:
> >> 
> >> [  740.250192896,3] LIBPORE: Core ID = 20 is not within valid range of [0;15]
> >> [  740.250230176,3] SLW: Failed to set spr for CPU 51
> >> 
> >> When trying to hotunplug core id 20. For now the
> >> patch just skips calling p8_pore* on p9 machines.
> >
> > STOP-API support in OPAL is provided by this patch set.
> >
> > https://lists.ozlabs.org/pipermail/skiboot/2017-August/008700.html
> > [Skiboot] [PATCH v3 0/7] Enable stop4 idle state
> >
> > We had a change to push to CCAN and that is resolved now.
> 
> Cool. I'll take Balbir's patch for now, as at least it closes a window
> where somebody could have an issue.

Ack.

> I'll revert this patch when looking at the stop4 enable series. For
> anyone working the weekend though, they'll have one less surprise.
> 
> Merged to master as of 0a2710381f34e6b4c03cff1fa76bc1b74f280ecd

Thanks for merging this fix.

This issue is not really related to stop4 enablement.   But kernel
unexpectedly calling into opal_slw_set_reg().

We should have closed these window early on and then add the new
features.  Lessons learnt. 

Thanks,
Vaidy