Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264448AbTHKQcn (ORCPT ); Mon, 11 Aug 2003 12:32:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272788AbTHKQc2 (ORCPT ); Mon, 11 Aug 2003 12:32:28 -0400 Received: from meryl.it.uu.se ([130.238.12.42]:51139 "EHLO meryl.it.uu.se") by vger.kernel.org with ESMTP id S264448AbTHKQ3b (ORCPT ); Mon, 11 Aug 2003 12:29:31 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16183.50273.723650.136532@gargle.gargle.HOWL> Date: Mon, 11 Aug 2003 18:29:21 +0200 From: Mikael Pettersson To: davej@redhat.com Cc: torvalds@transmeta.com, fxkuehl@gmx.de, linux-kernel@vger.kernel.org, willy@w.ods.org, marcelo@conectiva.com.br Subject: Re: [PATCH] Disable APIC on reboot. In-Reply-To: References: X-Mailer: VM 6.90 under Emacs 20.7.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1667 Lines: 47 davej@redhat.com writes: > diff -urpN --exclude-from=/home/davej/.exclude bk-linus/arch/i386/kernel/reboot.c linux-2.5/arch/i386/kernel/reboot.c > --- bk-linus/arch/i386/kernel/reboot.c 2003-05-13 11:51:12.000000000 +0100 > +++ linux-2.5/arch/i386/kernel/reboot.c 2003-07-16 02:54:29.000000000 +0100 > @@ -8,6 +8,7 @@ > #include > #include > #include > +#include > #include "mach_reboot.h" > > /* > @@ -250,6 +251,19 @@ void machine_restart(char * __unused) > */ > smp_send_stop(); > disable_IO_APIC(); > +#else > +#ifdef CONFIG_X86_LOCAL_APIC > + { > + unsigned int l, h; > + > + local_irq_disable(); > + disable_local_APIC(); > + rdmsr(MSR_IA32_APICBASE, l, h); > + l &= ~MSR_IA32_APICBASE_ENABLE; > + wrmsr(MSR_IA32_APICBASE, l, h); > + local_irq_enable(); > +} > +#endif I agree we should probably disable the local APIC at reboot if we enabled it previously, but this patch is broken. CONFIG_X86_LOCAL_APIC doesn't imply that the CPU actually has one, and even if it does, the access method may be different (e.g. P5 vs P6/K7/P4, and who knows how the future C3 with local APIC will do it). Only apic.c knows how the local APIC was initialised (if at all), so the "disable it dammit" procedure needs to be in apic.c too. Was the original bug report posted to LKML? I don't remember seeing it. /Mikael - 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/