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From: Bjorn Helgaas <helgaas@kernel.org>
To: Oliver O'Halloran <oohall@gmail.com>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	linux-pci@vger.kernel.org,
	Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
Subject: Re: [PATCH] powerpc/powernv: Disable native PCIe port management
Date: Thu, 14 Nov 2019 07:54:02 -0600	[thread overview]
Message-ID: <20191114135402.GA200503@google.com> (raw)
In-Reply-To: <CAOSf1CHzBJjxOd0f-CZcGPDW6S5GXMvw+6VmzBADJWeP2y1WAQ@mail.gmail.com>

On Fri, Nov 15, 2019 at 12:34:50AM +1100, Oliver O'Halloran wrote:
> On Thu, Nov 14, 2019 at 1:31 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
> >
> > This is fine, but it feels like sort of a blunt instrument.  Is there
> > any practical way to clear pci_host_bridge.native_pcie_hotplug (and
> > native_aer if appropriate) for the PHBs in question? That would also
> > prevent pciehp from binding.
> 
> It is a large hammer, but I don't see a better way to handle it for
> the moment. I had another look and my initial assessment was wrong in
> that it's the portbus driver which claims the MSI rather than pciehp
> itself. The MSI in the PCIe capability is shared between hotplug
> events, PMEs, and BW notifications so to make the portbus concept work
> the portbus driver needs to own the interrupt. Basicly, pnv_php and
> portbus are fundamentally at odds with each other and can't be used
> concurrently.

Yeah, that makes sense.  Is there a Kconfig symbol for pnv_php?  If
so, you could make CONFIG_PCIEPORTBUS unselectable in the first place.

But I'm guessing there isn't such a symbol because you probably want
to be able to build generic kernels that run on machines that *can*
use portdrv as well as on PowerNV.

So I'm find with the patch as posted.

Bjorn

  reply	other threads:[~2019-11-14 13:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-13  9:40 [PATCH] powerpc/powernv: Disable native PCIe port management Oliver O'Halloran
2019-11-13 14:31 ` Bjorn Helgaas
2019-11-14 13:34   ` Oliver O'Halloran
2019-11-14 13:54     ` Bjorn Helgaas [this message]
2019-11-13 20:39 ` Tyrel Datwyler
2019-11-14 13:37   ` Oliver O'Halloran
2019-11-15  4:28   ` Michael Ellerman

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