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

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Date:	Tue, 15 Jan 2008 05:57:27 +0800
From:	David Woodhouse <dwmw2@...radead.org>
To:	"David P. Reed" <dpreed@...d.com>
Cc:	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>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	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 Fri, 2008-01-11 at 09:35 -0500, David P. Reed wrote:
>   Using any "unused port" for a delay means that the machine check
> feature is wasted and utterly unusable.

Not entirely unusable. You can recover silently from the machine check
if it was one of the known accesses to the 'unused port'. It certainly
achieves a delay :)

On ppc32 we recover from the machine check if it was any inb/outb --
mostly to work around crappy drivers developed on i386, I believe.

-- 
dwmw2

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