Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754720AbXLNO6k (ORCPT ); Fri, 14 Dec 2007 09:58:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752439AbXLNO6c (ORCPT ); Fri, 14 Dec 2007 09:58:32 -0500 Received: from nf-out-0910.google.com ([64.233.182.184]:56653 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751633AbXLNO6b (ORCPT ); Fri, 14 Dec 2007 09:58:31 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding:from; b=OMrL2XWy28RnCDI+WM22ksLpeO+6zUcnP14maa1vGM92v5BqQfWoRfY5lJdsDV1NO/zDjmJe5cTnYPdeULHG01PH+5YX1Pfm45BjF1pItnGaRoeHlUIi3ThakpGRHj4VZHaZsfCWFHa3hrnEJtinRSKKTpuEwZxudUpG1Eidz4g= Message-ID: <476299B7.8030908@keyaccess.nl> Date: Fri, 14 Dec 2007 15:56:55 +0100 User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Ingo Molnar CC: Rene Herman , "David P. Reed" , Alan Cox , Thomas Gleixner , linux-kernel@vger.kernel.org, Ingo Molnar , "H. Peter Anvin" , Pavel Machek Subject: Re: [PATCH] x86_64: fix problems due to use of "outb" to port 80 on some AMD64x2 laptops, etc. References: <1184216528.12353.203.camel@chaos> <1184218962.12353.209.camel@chaos> <46964352.7040301@reed.com> <1184253339.12353.223.camel@chaos> <469697C6.50903@reed.com> <1184274754.12353.254.camel@chaos> <4761F193.7090400@reed.com> <476250D5.8000409@gmail.com> <20071214142355.GA10130@elte.hu> <476294D3.4060609@keyaccess.nl> <20071214144628.GA16074@elte.hu> In-Reply-To: <20071214144628.GA16074@elte.hu> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit From: Rene Herman Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1845 Lines: 44 On 14-12-07 15:46, Ingo Molnar wrote: > * Rene Herman wrote: > >>>> /* >>>> - * This should be approx 2 Bo*oMips to start (note initial shift), and will >>>> - * still work even if initially too large, it will just take slightly longer >>>> + * Initial value roughly corresponds to a 1 GHz CPU >>>> */ >>>> -unsigned long loops_per_jiffy = (1<<12); >>>> +unsigned long loops_per_jiffy = 1000000000 / HZ; >>>> >>>> EXPORT_SYMBOL(loops_per_jiffy); >>> this is a factor of ~2400 increase - this will take an eternity to boot on >>> any older CPU. >> Only any outb_p's used before loops_per_jiffy is calibrated are >> affected. > > yes - but there are a couple of early udelays, which would thus be > affected. True. At the moment though they're just always not delaying anywhere close the intended amount (on anything with more than 2 bogomips). Pre-calibration all this stuff is just broken it seems. >> This pre-calibation thing is what's historically held this change back >> (it's been discussed dozens of times before). At 4096, not any machine >> is going to have an appreciable delay before calibration when >> switching from the outb to 0x80. > > i dont think this should matter: old systems that truly _need_ the ISA > delay will be slow enough to not trip up. (nor are they really affected > by these early delays - the delays were more for crappy ISA devices that > get initialized later down, when the delay loop is already calibrated) 8253 (DMAC) and 8254 (PIT) have been reported in earlier versions of the thread. By Alan, I believe. 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/