Date: Wed, 16 Jan 2008 20:08:29 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: David Newall <davidn@davidnewall.com>
Cc: "David P. Reed" <dpreed@reed.com>, David Woodhouse <dwmw2@infradead.org>,
       Rene Herman <rene.herman@keyaccess.nl>,
       Zachary Amsden <zach@vmware.com>, "H. Peter Anvin" <hpa@zytor.com>,
       Christer Weinigel <christer@weinigel.se>,
       Ondrej Zary <linux@rainbow-software.org>, Bodo Eggert <7eggert@gmx.de>,
       Ingo Molnar <mingo@elte.hu>, Paul Rolland <rol@as2917.net>,
       Pavel Machek <pavel@ucw.cz>, Thomas Gleixner <tglx@linutronix.de>,
       linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
       rol <rol@witbe.net>
Subject: Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80
 I/O delay override.
Message-ID: <20080116200829.26040351@lxorguk.ukuu.org.uk>
In-Reply-To: <478E57C8.2080403@davidnewall.com>
References: <9BdU5-1YW-9@gated-at.bofh.it>
	<200801081810.58904.linux@rainbow-software.org>
	<4783B1B2.6070005@reed.com>
	<200801081838.16241.linux@rainbow-software.org>
	<4783C4A6.9060402@reed.com>
	<20080108185120.3ff7ed18@lxorguk.ukuu.org.uk>
	<4783CBD9.7020709@reed.com>
	<1199847162.7369.323.camel@bodhitayantram.eng.vmware.com>
	<47845972.9090803@zytor.com>
	<1199915614.7369.367.camel@bodhitayantram.eng.vmware.com>
	<47854916.4080703@reed.com>
	<1200015388.6192.22.camel@bodhitayantram.eng.vmware.com>
	<4786DD05.20804@keyaccess.nl>
	<47877ECD.9060408@reed.com>
	<1200347847.2647.97.camel@shinybook.infradead.org>
	<478BE08B.3090306@reed.com>
	<478E1668.9040404@davidnewall.com>
	<20080116145515.6d84dc7b@lxorguk.ukuu.org.uk>
	<478E57C8.2080403@davidnewall.com>
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> If the hardware required an intermediate junk I/O, that would be a
> reason to do one, but it doesn't, does it?  It requires a delay.  It's
> written thus in all of the application notes.

And the only instruction that is synchronized to the bus in question is
an I/O instruction. 

> Wrong again.  Of course one knows how long the delay should be.  The bus
> speed is known. 

Wrong again. ISA bus speed is neither defined precisely, nor visible in a
system portable fashion.

I'm so glad you have nothing better to do than troll, if you
actually wrote code I'd be worried it might get into something people
used.

Alan
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