Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756667AbXLGT0l (ORCPT ); Fri, 7 Dec 2007 14:26:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753389AbXLGT0c (ORCPT ); Fri, 7 Dec 2007 14:26:32 -0500 Received: from smtpq1.groni1.gr.home.nl ([213.51.130.200]:42518 "EHLO smtpq1.groni1.gr.home.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751008AbXLGT0b (ORCPT ); Fri, 7 Dec 2007 14:26:31 -0500 Message-ID: <47599E28.7020608@keyaccess.nl> Date: Fri, 07 Dec 2007 20:25:28 +0100 From: Rene Herman User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Alan Cox CC: Andi Kleen , "David P. Reed" , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Subject: Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops References: <475879CD.9080006@reed.com> <20071207160439.71b7f46a@the-village.bc.nu> <20071207163116.GB5992@one.firstfloor.org> <20071207171957.73b619b1@the-village.bc.nu> <475994C5.7090307@keyaccess.nl> <20071207184237.04174f42@the-village.bc.nu> In-Reply-To: <20071207184237.04174f42@the-village.bc.nu> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -1.0 (-) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1193 Lines: 32 On 07-12-07 19:42, Alan Cox wrote: > On Fri, 07 Dec 2007 19:45:25 +0100 > Rene Herman wrote: > >> On 07-12-07 18:19, Alan Cox wrote: >> >>> On Fri, 7 Dec 2007 17:31:16 +0100 >>> Andi Kleen wrote: >>> >>>>> You don't need to. Port 0x80 historically is about 8uS so just udelay(8) >>>>> and make sure the initial default delay is conservative enough before the >>>> How would you make it conservative enough handling let's say a 6Ghz CPU >>>> that can execute multiple jumps per cycle? >>> Pick a sane worst case and go with it at boot. We don't have to be >>> accurate before we tune udelay - over long in uSecs isnt going to hurt, >>> and most post boot _p's can be replaced by udelay(8) now >> Isn't 8 generally a bit overly long? I believe the norm is 1? > > 8uS is an ISA bus transaction. You very likely know better but just in case you're confused -- I thought it was 8 cycles... Rene. -- 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/