From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 4671ADDE46 for ; Fri, 10 Aug 2007 01:56:20 +1000 (EST) In-Reply-To: <46BB2CE2.2060207@freescale.com> References: <20070803201036.GA18229@ld0162-tx32.am.freescale.net> <46B88DAC.70005@freescale.com> , , <46BB2CE2.2060207@freescale.com> Mime-Version: 1.0 (Apple Message framework v623) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: <2b043cf24b0f5ddda06fcf1f01cb62f3@kernel.crashing.org> From: Segher Boessenkool Subject: Re: pci in arch/powerpc vs arch/ppc Date: Thu, 9 Aug 2007 17:56:05 +0200 To: Scott Wood Cc: linuxppc-dev@ozlabs.org, Alexandros Kostopoulos List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > It means the bus on which legacy I/O ports can be found. It's a fairly > broken concept; each host bridge should really be treated as a > completely separate entity, and if something like a VGA card has legacy > I/O ports that need to be used, they should be looked for on the same > PCI bus as the card itself. Legacy ISA ports should be discovered > through the device tree (or platform devices, or whatever) that > explicitly state which PCI-to-ISA bridge they're under. Currently, Linux does not allow multiple PCI domains to use overlapping legacy I/O ranges. Yeah it's a pain. > Yes, apparently -- according to a recent thread here, recent versions > of > the PCI spec removed the wording that prohibited a zero BAR (is there > then no way to disable a BAR?). I couldn't find that prohibition even in ancient versions of the PCI specification, for what it's worth. Maybe I'm just blind. > Still, it'd be better to avoid it. Yeah, many drivers go bonkers otherwise. Some devices might misbehave, too. Segher