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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Fri, 27 Jul 2018 18:18:51 +1000
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Subject: Re: [Qemu-devel] [PATCH v2 1/2] ppc/pnv: Add model for Power8 PHB3
 PCIe Host bridge
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To: =?ISO-8859-1?Q?C=E9dric?= Le Goater <clg@kaod.org>, David Gibson <david@gibson.dropbear.id.au>
Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Andrea Bolognani <abologna@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>

On Fri, 2018-07-27 at 09:16 +0200, C=C3=A9dric Le Goater wrote:
> > I'd have to remember how PQ works on P8 ... my gut feeling is that we
> > should resend if P=3D1 but I'm no 100% certain.
>=20
> This is not exactly what the code does. To force a resend, it ignores=20
> P but if Q=3D1, it bails out without doing anything, like a normal trig=
ger=20
> would do. So I think that in the resend case we should ignore Q as well.

Not too sure. We might need to swallow the resend if PQ became 01.

I don't know for sure what the HW does. Does it unconditionally resend
or does it re-evaluate the priority etc... it's unclear to me.

But yes, we should still resend if PQ=3D11

Cheers,
Ben.