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

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Message-ID: <alpine.LSU.0.999.0712311517360.4211@be1.lrz>
Date:	Mon, 31 Dec 2007 15:39:02 +0100 (CET)
From:	Bodo Eggert <7eggert@....de>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
cc:	"H. Peter Anvin" <hpa@...or.com>, 7eggert@....de,
	Ingo Molnar <mingo@...e.hu>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Rene Herman <rene.herman@...access.nl>, dpreed@...d.com,
	Islam Amer <pharon@...il.com>, Pavel Machek <pavel@....cz>,
	Ingo Molnar <mingo@...hat.com>,
	Andi Kleen <andi@...stfloor.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override

On Sun, 30 Dec 2007, Alan Cox wrote:
> On Sun, 30 Dec 2007 12:53:02 -0800
> "H. Peter Anvin" <hpa@...or.com> wrote:
> > Bodo Eggert wrote:

> > > I've never seen code which would do that, and it was not suggested by any
> > > tutorial I ever saw. I'd expect any machine to break on all kinds of software
> > > if it required this. The only thing I remember being warned about is writing
> > > the index and the data register at the same time using outw, because that
> > > would write both registers at the same time on 16-bit-cards.
> > > 
> > 
> > And we use that, and have been for 15 years.  I haven't seen any screams 
> > of pain about it.
> 
> Actually there were, and I sent numerous people patches for that back in
> ISA days. 

Are you talking about VGA cards requiring a delay between outb index/outb 
data, VGA cards barfing on outw or systems barfing on outb(0x80,42)?
-- 
Programming is an art form that fights back.
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