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From: "H. Peter Anvin" <hpa@zytor.com>
To: linux-kernel@vger.kernel.org
Subject: Re: VGA PCI IO port reservations
Date: 17 Nov 2000 18:10:13 -0800	[thread overview]
Message-ID: <8v4oe5$vbl$1@cesium.transmeta.com> (raw)
In-Reply-To: <200011172002.UAA01918@raistlin.arm.linux.org.uk> <Pine.LNX.3.95.1001117150349.23529A-100000@chaos.analogic.com> <20001117202009.B2472@zalem.puupuu.org>

Followup to:  <20001117202009.B2472@zalem.puupuu.org>
By author:    Olivier Galibert <galibert@pobox.com>
In newsgroup: linux.dev.kernel
> 
> What guarantees you that:
> 1- No device will respond 0xffff for an address it decodes
> 2- No device will crap up on you simply because you've read one
> particular address
> 
> If any of these if true for any device out there (I think I have one
> in my computer that does the 1/ part in some cases), your code is
> unsafe.
> 

It is.  There are plenty of devices for which an arbitrary IN is an
irrecoverable state transition.

	-hpa
-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt
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  reply	other threads:[~2000-11-18  2:41 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2000-11-17 16:20 VGA PCI IO port reservations Russell King
2000-11-17 16:36 ` Jeff Garzik
2000-11-17 16:46   ` Russell King
2000-11-17 16:52     ` Jeff Garzik
2000-11-17 16:58       ` Russell King
2000-11-17 17:03         ` Jeff Garzik
2000-11-17 17:11           ` Russell King
2000-11-17 21:43     ` Matthew Kirkwood
2000-11-17 22:02       ` H. Peter Anvin
2000-11-18 17:41         ` About IOs, ISA, PCI, and life (WAS: VGA PCI IO port...) Benjamin Herrenschmidt
2000-11-17 17:13   ` VGA PCI IO port reservations Richard B. Johnson
2000-11-17 17:20     ` Russell King
2000-11-17 17:30       ` Alan Cox
2000-11-17 18:06       ` Richard B. Johnson
2000-11-17 19:52         ` Russell King
2000-11-17 19:59           ` Richard B. Johnson
2000-11-17 20:02             ` Russell King
2000-11-17 20:27               ` Richard B. Johnson
2000-11-18  1:20                 ` Olivier Galibert
2000-11-18  2:10                   ` H. Peter Anvin [this message]
2000-11-18 17:02                     ` Alan Cox
2000-11-27 22:10                       ` Kai Henningsen
2000-11-17 21:35             ` Marcus Sundberg
2000-11-17 20:13           ` H. Peter Anvin
2000-11-17 20:31             ` Richard B. Johnson
2000-11-17 16:47 ` Brian Gerst
2000-11-17 16:56   ` Russell King
2000-11-17 17:00     ` Jeff Garzik
2000-11-17 18:29     ` H. Peter Anvin
2000-11-17 18:27 ` H. Peter Anvin

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