Re: [PATCH -v2] x86, pci: Handle fallout pci devices with peer root bus

From: "H. Peter Anvin" <hpa@zytor.com>
To: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Yinghai Lu <yinghai.lu@oracle.com>,
	Jesse Barnes <jbarnes@virtuousgeek.org>,
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
	Graham Ramsey <ramsey.graham@ntlworld.com>,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
	Robert Richter <robert.richter@amd.com>,
	Harald Welte <HaraldWelte@viatech.com>,
	Joseph Chan <JosephChan@via.com.tw>, Jiri Slaby <jslaby@suse.cz>,
	Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dominik Brodowski <linux@dominikbrodowski.net>
Subject: Re: [PATCH -v2] x86, pci: Handle fallout pci devices with peer root bus
Date: Mon, 14 Jun 2010 14:10:20 -0700	[thread overview]
Message-ID: <4C169ABC.1090406@zytor.com> (raw)
In-Reply-To: <201006141420.15799.bjorn.helgaas@hp.com>

On 06/14/2010 01:20 PM, Bjorn Helgaas wrote:
> 
> OK, but Graham's system doesn't have anything resembling a PCI-to-PCI
> bridge leading to bus 80.  So while I agree that in an ideal world,
> HT/PCI host bridges might always look like PCI-to-PCI bridges, it
> seems this is not the case in practice.
> 

Invisible PCI bridges have been known to occur in pure PCI space, too.

> Yes, absolutely.  My point is that what the HT spec means by "host bridge"
> is not the same as what the PCI spec and Linux mean by "PCI host bridge".

Actually, they're *exactly* the same thing.

	-hpa