Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 6 Aug 2002 09:40:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 6 Aug 2002 09:40:10 -0400 Received: from willy.net1.nerim.net ([62.212.114.60]:18960 "EHLO www.home.local") by vger.kernel.org with ESMTP id ; Tue, 6 Aug 2002 09:40:09 -0400 Date: Tue, 6 Aug 2002 15:43:28 +0200 From: Willy TARREAU To: marcelo@conectiva.com.br Cc: linux-kernel@vger.kernel.org Subject: [PATCH] APM fix for 2.4.20pre1 Message-ID: <20020806134328.GA587@pcw.home.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2336 Lines: 83 Hi Marcelo, I resend you this patch against 2.4.19-rc5 which prevents my SMP box from randomly crashing at boot during APM initialization. It still applies to 2.4.20-pre1. Alan included it in 19-ac4 too. Basically, it forces bios calls to be made only from CPU0. Please include it in 2.4.20-pre2. Thanks, Willy PS: people using O(1) scheduler should not use this patch, but Alan's. --- linux-2.4.19-rc5/arch/i386/kernel/apm.c Thu Aug 1 22:07:39 2002 +++ linux-2.4.19-rc5-fix/arch/i386/kernel/apm.c Fri Aug 2 01:52:55 2002 @@ -862,14 +862,6 @@ apm_do_busy(); } -#ifdef CONFIG_SMP -static int apm_magic(void * unused) -{ - while (1) - schedule(); -} -#endif - /** * apm_power_off - ask the BIOS to power off * @@ -897,10 +889,11 @@ */ #ifdef CONFIG_SMP /* Some bioses don't like being called from CPU != 0 */ - while (cpu_number_map(smp_processor_id()) != 0) { - kernel_thread(apm_magic, NULL, - CLONE_FS | CLONE_FILES | CLONE_SIGHAND | SIGCHLD); + if (cpu_number_map(smp_processor_id()) != 0) { + current->cpus_allowed = 1; schedule(); + if (unlikely(cpu_number_map(smp_processor_id()) != 0)) + BUG(); } #endif if (apm_info.realmode_power_off) @@ -1661,6 +1654,21 @@ strcpy(current->comm, "kapmd"); sigfillset(¤t->blocked); +#ifdef CONFIG_SMP + /* 2002/08/01 - WT + * This is to avoid random crashes at boot time during initialization + * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D. + * Some bioses don't like being called from CPU != 0. + * Method suggested by Ingo Molnar. + */ + if (cpu_number_map(smp_processor_id()) != 0) { + current->cpus_allowed = 1; + schedule(); + if (unlikely(cpu_number_map(smp_processor_id()) != 0)) + BUG(); + } +#endif + if (apm_info.connection_version == 0) { apm_info.connection_version = apm_info.bios.version; if (apm_info.connection_version > 0x100) { @@ -1707,7 +1715,7 @@ } } - if (debug && (smp_num_cpus == 1)) { + if (debug) { error = apm_get_power_status(&bx, &cx, &dx); if (error) printk(KERN_INFO "apm: power status not available\n"); - 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/