Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758901AbYAHAMR (ORCPT ); Mon, 7 Jan 2008 19:12:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758539AbYAHAL5 (ORCPT ); Mon, 7 Jan 2008 19:11:57 -0500 Received: from mho-01-bos.mailhop.org ([63.208.196.178]:61616 "EHLO mho-01-bos.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758517AbYAHALz (ORCPT ); Mon, 7 Jan 2008 19:11:55 -0500 X-Mail-Handler: MailHop Outbound by DynDNS X-Originating-IP: 216.15.117.105 X-Report-Abuse-To: abuse@dyndns.com (see http://www.mailhop.org/outbound/abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX19ZFAAggQUbzQCKA0Cc/Tvx Message-ID: <4782BF77.80703@reed.com> Date: Mon, 07 Jan 2008 19:10:31 -0500 From: "David P. Reed" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.8.1.9) Gecko/20071115 Fedora/2.0.0.9-1.fc8 Thunderbird/2.0.0.9 Mnenhy/0.7.5.0 MIME-Version: 1.0 To: Rene Herman CC: "H. Peter Anvin" , Bodo Eggert <7eggert@gmx.de>, Christer Weinigel , Ingo Molnar , Alan Cox , Paul Rolland , Pavel Machek , Thomas Gleixner , linux-kernel@vger.kernel.org, Ingo Molnar , rol@witbe.net Subject: Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override. References: <9BdU5-1YW-9@gated-at.bofh.it> <9BeZN-3Gf-5@gated-at.bofh.it> <9BnTB-1As-31@gated-at.bofh.it> <9BrX4-8go-1@gated-at.bofh.it> <9BuBG-4eR-51@gated-at.bofh.it> <9BvRd-6aL-71@gated-at.bofh.it> <9GRQW-1DX-13@gated-at.bofh.it> <9GSah-23W-1@gated-at.bofh.it> <9GSDy-2GD-23@gated-at.bofh.it> <9GTpK-40d-15@gated-at.bofh.it> <9GUvy-5H2-11@gated-at.bofh.it> <9GVKU-7SS-25@gated-at.bofh.it> <478281A6.1000704@zytor.com> <4782A355.1070207@zytor.com> <4782AED5.1060406@keyaccess.nl> <4782B4B9.2020608@zytor.com> <4782B515.3010008@keyaccess.nl> In-Reply-To: <4782B515.3010008@keyaccess.nl> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2024 Lines: 39 On another topic. I have indeed determined what device uses port 80 on Quanta AMD64 laptops from HP. I had lunch with Jim Gettys of OLPC a week ago; he's an old friend since he worked on the original X windows system. After telling him my story about port 80, he mentioned that the OLPC XO machine had some issues with port 80 which was by design handled by the ENE KBC device on its motherboard. He said the ENE was a very desirable chipset for AMD designs recommended by Quanta. Richard Smith of OLPC explained to me how the KB3700 they use works, and that they use the KB3700 to send POST codes out over a serial link during boot up. This gave me a reason to take apart my laptop, to discover that it has an ENE KB3920 B0 as its EC and KBC. The port interface for the KB3920 includes listening to port 80 which is then made available to firmware on the EC. It is recognized and decoded on the LPC bus, only for writes, and optionally can generate an interrupt in the 8051. Dumping both the ENE chip, and looking at the DSDT.dsl for my machine, I discovered that port 80 is used as an additional parameter for various DSDT methods that communicate to the EC, when it is operating in ACPI mode. More work is in progress as I play around with this. But the key thing is that ACPI and perhaps SMM both use port 80 as part of the base function of the chipset. And actually, if I had looked at the /sys/bus/pnp definitions, rather than /proc/ioports, I would have noticed that port 80 was part of a PNP0C02 resource set. That means exactly one thing: ACPI says that port 80 is NOT free to be used, for delays or anything else. This should make no difference here: it's just one more reason to stop using port 80 for delays on modern machines. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/