Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268626AbTGOPRN (ORCPT ); Tue, 15 Jul 2003 11:17:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268470AbTGOPPf (ORCPT ); Tue, 15 Jul 2003 11:15:35 -0400 Received: from chaos.analogic.com ([204.178.40.224]:41092 "EHLO chaos.analogic.com") by vger.kernel.org with ESMTP id S268522AbTGOPOY (ORCPT ); Tue, 15 Jul 2003 11:14:24 -0400 Date: Tue, 15 Jul 2003 11:31:17 -0400 (EDT) From: "Richard B. Johnson" X-X-Sender: root@chaos Reply-To: root@chaos.analogic.com 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 In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1866 Lines: 60 On Tue, 15 Jul 2003, 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. Is there a more > appropriate way to handle a short timeout? It will truncate it at runtime. I suggest dmatimer.expires = jiffies + HZ/2; Also, you you need to use the time_before() macro, like while ( time_before(jiffies, dmatimer.expires) ) do_something(); ... so you don't have a timer-wrap problem during jiffie rollover if you haven't already done so (I don't have your source here). > > Thanks, > Kathy Cheers, Dick Johnson Penguin : Linux version 2.4.20 on an i686 machine (797.90 BogoMips). Why is the government concerned about the lunatic fringe? Think about it. - 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/