Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756436Ab2HNOY3 (ORCPT ); Tue, 14 Aug 2012 10:24:29 -0400 Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:41703 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756368Ab2HNOYZ (ORCPT ); Tue, 14 Aug 2012 10:24:25 -0400 MIME-Version: 1.0 In-Reply-To: <20120814114856.GA17040@linux-mips.org> References: <1344862344-27434-1-git-send-email-chenhc@lemote.com> <20120814114856.GA17040@linux-mips.org> Date: Tue, 14 Aug 2012 22:24:23 +0800 X-Google-Sender-Auth: OdjvaVSow-eFKblR3wnQTBWGSpk Message-ID: Subject: Re: [PATCH V2] MIPS: Fix poweroff failure when HOTPLUG_CPU configured. From: Huacai Chen To: Ralf Baechle Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, Fuxin Zhang , Zhangjin Wu , Hongliang Tao , Hua Yan , Yong Zhang , stable@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1861 Lines: 43 On Tue, Aug 14, 2012 at 7:48 PM, Ralf Baechle wrote: > On Mon, Aug 13, 2012 at 08:52:24PM +0800, Huacai Chen wrote: > >> When poweroff machine, kernel_power_off() call disable_nonboot_cpus(). >> And if we have HOTPLUG_CPU configured, disable_nonboot_cpus() is not an >> empty function but attempt to actually disable the nonboot cpus. Since >> system state is SYSTEM_POWER_OFF, play_dead() won't be called and thus >> disable_nonboot_cpus() hangs. Therefore, we make this patch to avoid >> poweroff failure. > >> diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c >> index e9a5fd7..69b17a9 100644 >> --- a/arch/mips/kernel/process.c >> +++ b/arch/mips/kernel/process.c >> @@ -72,9 +72,7 @@ void __noreturn cpu_idle(void) >> } >> } >> #ifdef CONFIG_HOTPLUG_CPU >> - if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map) && >> - (system_state == SYSTEM_RUNNING || >> - system_state == SYSTEM_BOOTING)) >> + if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map)) > > Looks good - but I'm wondering if the "!cpu_isset(cpu, cpu_callin_map)" > can be removed as well? For X86, IA64, ARM, SPARC64 and most other arch, "!cpu_online(cpu)" is the only condition of play_dead(). I keep "!cpu_isset(cpu, cpu_callin_map)" because this does't refuse poweroff and I don't know why the old condition of play_dead() is so complex. > > Also, which -stable branches is this patch applicable? 3.3, 3.4 and 3.5 branch can use it, 3.2 and earlier kernels should do some small changes. > > Ralf > -- 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/