From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 11 May 2002 07:49:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 11 May 2002 07:49:19 -0400 Received: from harpo.it.uu.se ([130.238.12.34]:17577 "EHLO harpo.it.uu.se") by vger.kernel.org with ESMTP id ; Sat, 11 May 2002 07:49:19 -0400 Date: Sat, 11 May 2002 13:47:57 +0200 (MET DST) From: Mikael Pettersson Message-Id: <200205111147.NAA07199@harpo.it.uu.se> To: hch@infradead.org Subject: 2.4.19-pre7+ I/O-APIC inconsistency Cc: linux-kernel@vger.kernel.org, marcelo@conectiva.com.br Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 2.4.19-pre7 changed the behaviour of CONFIG_X86_UP_IOAPIC due to the following patch --- linux-2.4.19-pre6/arch/i386/kernel/io_apic.c Mon Apr 15 21:53:25 2002 +++ linux-2.4.19-pre7/arch/i386/kernel/io_apic.c Mon Apr 15 21:54:19 2002 @@ -191,15 +191,27 @@ #define MAX_PIRQS 8 int pirq_entries [MAX_PIRQS]; int pirqs_enabled; -int skip_ioapic_setup; +#ifdef CONFIG_X86_UP_APIC +int skip_ioapic_setup=1; +#else +int skip_ioapic_setup=0; +#endif which patch-2.4.19.log seems to attribute to . This causes CONFIG_X86_UP_IOAPIC to no longer attempt to use the I/O-APIC like it used to: now you also have to append an "apic" command-line option to the kernel. Not only is this a break from previous behaviour and the documentation (Configure.help), but it's also inconsistent with SMP, since an SMP kernel _will_ try to use the I/O-APIC without any additional hackery needed. (I just helped some high-speed Linux routing colleagues over here debug a problem with their new dual P4 Xeon E7500 chipset boxes. SMP kernels worked, but they couldn't figure out why UP_IOAPIC kernels wouldn't detect and use the I/O-APIC. The patch above was the culprit.) Unless this change is absolutely necessary (note that the "noapic" command line option is still functional for those that need it), I suggest applying the patch below to restore the previous behaviour. /Mikael --- linux-2.4.19-pre8/arch/i386/kernel/io_apic.c.~1~ Sat May 11 12:30:26 2002 +++ linux-2.4.19-pre8/arch/i386/kernel/io_apic.c Sat May 11 12:37:06 2002 @@ -191,11 +191,7 @@ #define MAX_PIRQS 8 int pirq_entries [MAX_PIRQS]; int pirqs_enabled; -#ifdef CONFIG_X86_UP_APIC -int skip_ioapic_setup=1; -#else -int skip_ioapic_setup=0; -#endif +int skip_ioapic_setup; static int __init noioapic_setup(char *str) {