linux-kernel - Re: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

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Message-ID: <20080116145515.6d84dc7b@lxorguk.ukuu.org.uk>
Date:	Wed, 16 Jan 2008 14:55:15 +0000
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	David Newall <davidn@...idnewall.com>
Cc:	"David P. Reed" <dpreed@...d.com>,
	David Woodhouse <dwmw2@...radead.org>,
	Rene Herman <rene.herman@...access.nl>,
	Zachary Amsden <zach@...are.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Christer Weinigel <christer@...nigel.se>,
	Ondrej Zary <linux@...nbow-software.org>,
	Bodo Eggert <7eggert@....de>, Ingo Molnar <mingo@...e.hu>,
	Paul Rolland <rol@...917.net>, Pavel Machek <pavel@....cz>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	rol <rol@...be.net>
Subject: Re: Re: [PATCH] x86: provide a DMI based port 0x80
 I/O delay override.

On Thu, 17 Jan 2008 01:06:24 +1030
David Newall <davidn@...idnewall.com> wrote:

> This use of port 80 (or insert some other random number) is a croc of
> hackery of the most inexperienced kind. 

Wrong. It's a careful designed solution used by all sorts of code for
over 15 years.

 The task to be performed is to delay for some period

Wrong, it is for some number of bus clocks which is why I/O cycles are
used

> that an OUT is used because you don't know how long the delay should be
> on any specific machine.  What rubbish.

Wrong again.

> I won't even mention the many instances of these delays where no delay
> is what properly is needed.  Performance?  Who cares about performance?

Correctness, who needs correctness ?

Alan
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