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

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Message-Id: <1200015388.6192.22.camel@bodhitayantram.eng.vmware.com>
Date:	Thu, 10 Jan 2008 17:36:28 -0800
From:	Zachary Amsden <zach@...are.com>
To:	"David P. Reed" <dpreed@...d.com>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Christer Weinigel <christer@...nigel.se>,
	Ondrej Zary <linux@...nbow-software.org>,
	Rene Herman <rene.herman@...access.nl>,
	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 Wed, 2008-01-09 at 17:22 -0500, David P. Reed wrote:
> Zachary Amsden wrote:
> >
> > According to Phoenix Technologies book "System BIOS for IBM PCs,
> > Compatibles and EISA Computers, 2nd Edition", the I/O port list gives
> >
> > port 0080h   R/W  Extra page register (temporary storage)
> >
> > Despite looking, I've never seen it documented anywhere else, but I
> > believe it works on just about every PC platform.  Except, apparently,
> > my laptop.
> >
> >
> >   
> The port 80 problem was discovered by me, after months of "bisecting" 
> the running code around a problem with hanging when using hwclock in 
> 64-bit mode when ACPI is on.  So it kills my laptop, too, and many 
> currentlaptop motherboards designed by Quanta for HP and Compaq (dv6000, 
> dv9000, tx1000, apparently)

Thanks very much for that - I was debugging this for a while too, and
eventually just shut off hwclock.

> Your laptop isn't an aberration.  It's part of the new generation of 
> evolved machines that take advantage of the capabilities of ACPI and 
> SMBIOS and DMI standards that are becoming core parts of the market.

I beg to differ.  I managed to turn the thing into a brick by upgrading
the BIOS (with the correct image, no less) in an attempt to fix it.  I
just got it back from repair.  I'm not sure that is positive
evolutionary development, but it certainly does make my laptop an
aberration :)

FWIW, I fixed the problem locally by recompiling, changing port 80 to
port 84 in io.h; works great, and doesn't conflict with any occupied
ports.

Zach

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