Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268962AbTGOQvj (ORCPT ); Tue, 15 Jul 2003 12:51:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268964AbTGOQvi (ORCPT ); Tue, 15 Jul 2003 12:51:38 -0400 Received: from mail5.iserv.net ([204.177.184.155]:22180 "EHLO mail5.iserv.net") by vger.kernel.org with ESMTP id S268962AbTGOQvf (ORCPT ); Tue, 15 Jul 2003 12:51:35 -0400 Message-ID: <3F14348B.4050606@didntduck.org> Date: Tue, 15 Jul 2003 13:06:19 -0400 From: Brian Gerst User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.4) Gecko/20030624 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Kathy Frazier CC: Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: Interrupt doesn't make it to the 8259 on a ASUS P4PE mobo References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1461 Lines: 50 Kathy Frazier wrote: > Thanks for your reply, Andi. > > >>>We have a proprietary PCI board installed in a (UP) system with an ASUS > > P4PE > >>>motherboard (uses Intel 845PE chipset). This system is running Red Hat > > 9.0 > > >>Have you checked the 845 errata sheets on the Intel website? >>Perhaps it is some known hardware bug. > > >>One thing you could try is to use Local APIC / IO APIC interrupt processing >>instead of 8259. > > > Our hardware engineer has combed the Intel and ASUS websites, but found > nothing. I'll give the APIC a try and see if I get different results and > let you know. > > >>>/* start timer */ >>>dmatimer.expires = jiffies + 0.5*HZ; > > >>That's a serious bug. You cannot use floating point in the kernel. >>It will corrupt the FP state of the user process. > > > HZ on the INTEL platform is 100, so this should simply add 50 to the current > value of jiffies. Besides, assigning the value to the unsigned int field > (expires) will truncate it to an integer anyway. Use HZ/2 instead. GCC doesn't optimize floating point constants to the same degree it does integers, because it doesn't know what mode (rounding, precision) the FPU is in. -- Brian Gerst - 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/