From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+w=401wt.eu-S1753805AbXLKRDD@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1753805AbXLKRDD (ORCPT <rfc822;w@1wt.eu>);
	Tue, 11 Dec 2007 12:03:03 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755915AbXLKRCY
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Tue, 11 Dec 2007 12:02:24 -0500
Received: from terminus.zytor.com ([198.137.202.10]:58449 "EHLO
	terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1755901AbXLKRCW (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 11 Dec 2007 12:02:22 -0500
Message-ID: <475EC24E.4070900@zytor.com>
Date: Tue, 11 Dec 2007 09:01:02 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
User-Agent: Thunderbird 2.0.0.9 (X11/20071115)
MIME-Version: 1.0
To: Rene Herman <rene.herman@keyaccess.nl>
CC: David Newall <david@davidnewall.com>, Krzysztof Halasa <khc@pm.waw.pl>,
       Pavel Machek <pavel@ucw.cz>, Andi Kleen <andi@firstfloor.org>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, "David P. Reed" <dpreed@reed.com>,
       linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       Ingo Molnar <mingo@redhat.com>
Subject: Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64
 with MCP51 laptops
References: <475879CD.9080006@reed.com> <p733auekcly.fsf@bingen.suse.de>	<20071207160439.71b7f46a@the-village.bc.nu>	<20071209125458.GB4381@ucw.cz>	<20071209165908.GA15910@one.firstfloor.org>	<20071209212513.GC24284@elf.ucw.cz> <475CBDD7.5050602@keyaccess.nl> <m3bq8y23de.fsf@maximus.localdomain> <475DE37F.20706@davidnewall.com> <475DE6F4.80702@zytor.com> <475E341F.9000107@keyaccess.nl>
In-Reply-To: <475E341F.9000107@keyaccess.nl>
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Rene Herman wrote:
> On 11-12-07 02:25, H. Peter Anvin wrote:
> 
>> David Newall wrote:
>>> Where did the 8us delay come from?  The documentation and source is 
>>> careful not to say how long the delay is.  Would changing it to, say 
>>> 1us, be technically wrong?  Is code that requires 8us correct?
>>
>> I think a single ISA bus transaction is 1 µs, so two of them back to 
>> back should be 2 µs, not 8 µs...
> 
> Sigh. And now where do these _two_ transactions come from? (and yes, see 
> Alan's folowups, a transaction on a spec bus is 1 us).
> 

Stale memory, sorry.

	-hpa