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Subject: Re: [PATCH v7 39/50] powerpc/powernv: Fundamental reset in
 pnv_pci_reset_secondary_bus()
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Daniel Axtens <dja@axtens.net>, Gavin Shan <gwshan@linux.vnet.ibm.com>,
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Cc: linux-pci@vger.kernel.org, devicetree@vger.kernel.org, mpe@ellerman.id.au,
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Date: Fri, 13 Nov 2015 11:23:23 +1100
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On Fri, 2015-11-13 at 11:08 +1100, Daniel Axtens wrote:
> Gavin Shan <gwshan@linux.vnet.ibm.com> writes:
> 
> >  void pnv_pci_reset_secondary_bus(struct pci_dev *dev)
> >  {
> > -> > 	> > pnv_eeh_bridge_reset(dev, EEH_RESET_HOT);
> > +> > 	> > int option, freset = 0;
> > +
> > +> > 	> > if (dev->subordinate)
> > +> > 	> > 	> > pci_walk_bus(dev->subordinate,
> > +> > 	> > 	> > 	> >      pnv_pci_dev_reset_type, &freset);
> > +
> > +> > 	> > option = freset ? EEH_RESET_FUNDAMENTAL : EEH_RESET_HOT;
> > +> > 	> > pnv_eeh_bridge_reset(dev, option);
> 
> According to the skiboot sources, fundamental reset isn't supported on
> p5ioc2. As far as I can tell from your corresponding skiboot patches,
> this is still the case after they are applied. Do we need a fallback to
> EEH_RESET_HOT in this case? Otherwise there will be no reset performed
> at all.

We don't really care that much about what happens on p5ioc2 :-)

> Likewise, if the FUNDAMENTAL reset fails for any reason, should we fall
> back to a HOT reset?

Probably.

Cheers,
Ben.