Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937239AbXLQVDQ (ORCPT ); Mon, 17 Dec 2007 16:03:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761614AbXLQVDA (ORCPT ); Mon, 17 Dec 2007 16:03:00 -0500 Received: from mho-01-bos.mailhop.org ([63.208.196.178]:58017 "EHLO mho-01-bos.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761733AbXLQVC7 (ORCPT ); Mon, 17 Dec 2007 16:02:59 -0500 X-Mail-Handler: MailHop Outbound by DynDNS X-Originating-IP: 18.85.9.136 X-Report-Abuse-To: abuse@dyndns.com (see http://www.mailhop.org/outbound/abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX18bGL23J7FUm+yxDu+I0wMg Message-ID: <4766E3DC.50700@reed.com> Date: Mon, 17 Dec 2007 16:02:20 -0500 From: "David P. Reed" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.8.1.5) Gecko/20070727 Fedora/2.0.0.5-2.fc7 Thunderbird/2.0.0.5 Mnenhy/0.7.5.0 MIME-Version: 1.0 To: "H. Peter Anvin" CC: Rene Herman , Ingo Molnar , Paul Rolland , Alan Cox , Pavel Machek , Thomas Gleixner , linux-kernel@vger.kernel.org, Ingo Molnar , rol@witbe.net Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override. References: <4762C551.5070003@zytor.com> <20071214210652.GB28793@elf.ucw.cz> <4763001A.1070102@zytor.com> <20071214232955.545ab809@the-village.bc.nu> <20071215080831.404cdb32@tux.DEF.witbe.net> <47638C8C.2090604@gmail.com> <476438B4.2020600@zytor.com> <476462BE.3030701@gmail.com> <4764687D.6080609@zytor.com> <476524DB.7020806@gmail.com> <20071216152250.GA21245@elte.hu> <4765D43E.1010800@gmail.com> <4765D95C.4010404@zytor.com> <4765DCB0.8030901@gmail.com> <4765EE7F.80002@zytor.com> <47667366.7010405@gmail.com> <4766AE88.4080904@zytor.com> <4766D175.7040807@reed.com> <4766D443.6040805@zytor.com> In-Reply-To: <4766D443.6040805@zytor.com> 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: 1455 Lines: 39 H. Peter Anvin wrote: > David P. Reed wrote: >> As support: port 80 on the reporter's (my) HP dv9000z laptop clearly >> responds to reads differently than "unused" ports. In particular, an >> inb takes 1/2 the elapsed time compared to a read to "known" unused >> port 0xed - 792 tsc ticks for port 80 compared to about 1450 tsc >> ticks for port 0xed and other unused ports (tsc at 800 MHz). >> > > Any timings for port 0xf0 (write zero), out of curiosity? > Here's a bunch of data: port 0xF0: cycles: out 919, in 933 port 0xed: cycles: out 2541, in 2036 port 0x70: cycles: out n/a, in 934 port 0x80: cycles: out 1424, in 795 AMD Turion 64x2 TL-60 CPU running at 800 MHz, nVidia MCP51 chipset, Quanta motherboard. Running 2.6.24-rc5 with Ingo's patch so inb_p, etc. use port 0xed. Note that I can run the port 80 test once, the second time I get the hard freeze. I didn't try writing to port 70 from userspace - that one's dangerous, but the reading of it was included for a timing typical of a chipset supported device. These are all pretty consistent. I find the "read" timing from 0x80 verrrrry interesting. The write timeing is also interesting, being faster than an unused port. -- 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/