From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755979AbXJJKG0 (ORCPT ); Wed, 10 Oct 2007 06:06:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755136AbXJJKGS (ORCPT ); Wed, 10 Oct 2007 06:06:18 -0400 Received: from sullivan.realtime.net ([205.238.132.226]:2032 "EHLO sullivan.realtime.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752284AbXJJKGQ (ORCPT ); Wed, 10 Oct 2007 06:06:16 -0400 Date: Wed, 10 Oct 2007 05:06:05 -0500 (CDT) Message-Id: <200710101006.l9AA657g083900@sullivan.realtime.net> From: Milton Miller To: Linus Torvalds , "Rafael J. Wysocki" , Mark Lord Cc: , Thomas Gleixner , Andrew Morton , Greg Kroah-Hartman , Subject: Re: [stable] [patch 09/12] Fix SMP poweroff hangs References: <20071008180406.052382073@mini.kroah.org>, <20071008180633.GJ7627@kroah.com>, <20071009151702.GA19209@lixom.net>, <20071009222003.GA21228@kroah.com>, , , Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 9 2007 Thomas Gleixner wrote: >On Tue, 9 Oct 2007, Linus Torvalds wrote: >>On Wed, 10 Oct 2007, Thomas Gleixner wrote: >>> >>> Wrapping it into a #ifdef CONFIG_X86 would be sufficient. >> >> Well, the ppc oops seems to be a ppc bug regardless. >> >> If CPU_HOTPLUG isn't defined, the thing does nothing. And if it is >> defined, I don't see why/how ppc can validly oops. So I think the first >> thing to do is to try to figure out why it oopses, not to disable it for >> ppc. > >Fair enough. OTOH for the affected PPC users it's a regression and that's >what I'm concerned of. > >tglx I agree this exposes a ppc arch bug (and the reason has been diagnosed), but might not other archs have similar problems? The patch ties power-off code to suspend and hibernate cpu hotplug code. Why not put this ACPI requirement in the ACPI code? There is already a hook called at the same place this function was called that is only used for power off. Also, the code is compiled for CONFIG_PM_SLEEP_SMP, which is not CONFIG_HOTPLUG_CPU, it requires the selection of either CONFIG_HIBERNATION or CONFIG_SUSPEND. I confirmed that both of these can be disabled on i386 without disabling acpi. In such a kernel the existing patch is insufficient. drivers/acpi/sleep/main.c | 2 ++ kernel/sys.c | 1 - 2 files changed, 2 insertions(+), 1 deletions(-) diff --git a/drivers/acpi/sleep/main.c b/drivers/acpi/sleep/main.c index 2cbb9aa..79589bd 100644 --- a/drivers/acpi/sleep/main.c +++ b/drivers/acpi/sleep/main.c @@ -15,6 +15,7 @@ #include #include #include +#include #include @@ -382,6 +383,7 @@ static void acpi_power_off_prepare(void) { /* Prepare to power off the system */ acpi_sleep_prepare(ACPI_STATE_S5); + disable_nonboot_cpus(); } static void acpi_power_off(void) diff --git a/kernel/sys.c b/kernel/sys.c index 8ae2e63..138f5c8 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -879,7 +879,6 @@ void kernel_power_off(void) kernel_shutdown_prepare(SYSTEM_POWER_OFF); if (pm_power_off_prepare) pm_power_off_prepare(); - disable_nonboot_cpus(); sysdev_shutdown(); printk(KERN_EMERG "Power down.\n"); machine_power_off();