From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934721Ab3DHCv6 (ORCPT ); Sun, 7 Apr 2013 22:51:58 -0400 Received: from mail.lemote.com ([222.92.8.138]:44167 "EHLO mail.lemote.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934661Ab3DHCv5 (ORCPT ); Sun, 7 Apr 2013 22:51:57 -0400 Message-ID: <6c971a50f7639f17b1c419b6a885409b.squirrel@mail.lemote.com> In-Reply-To: <2582863.XOOaeZz0rz@vostro.rjw.lan> References: <1365300854-3133-1-git-send-email-chenhc@lemote.com> <3513307.9cks2gqsZt@vostro.rjw.lan> <20130407152932.GA18032@kroah.com> <2582863.XOOaeZz0rz@vostro.rjw.lan> Date: Mon, 8 Apr 2013 10:51:45 +0800 Subject: Re: [PATCH] PM/reboot: call syscore_shutdown() after disable_nonboot_cpus() From: chenhc@lemote.com To: "Rafael J. Wysocki" Cc: "Greg KH" , "Andrew Morton" , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, "Fuxin Zhang" , stable@vger.kernel.org User-Agent: SquirrelMail/1.4.22 MIME-Version: 1.0 Content-Type: text/plain;charset=gb2312 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Sunday, April 07, 2013 08:29:32 AM Greg KH wrote: >> On Sun, Apr 07, 2013 at 10:46:00AM +0200, Rafael J. Wysocki wrote: >> > On Sunday, April 07, 2013 10:14:14 AM Huacai Chen wrote: >> > > As commit 40dc166c (PM / Core: Introduce struct syscore_ops for core >> > > subsystems PM) say, syscore_ops operations should be carried with >> one >> > > CPU on-line and interrupts disabled. However, after commit f96972f2d >> > > (kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()), >> > > syscore_shutdown() is called before disable_nonboot_cpus(), so break >> > > the rules. We have a MIPS machine with a 8259A PIC, and there is an >> > > external timer (HPET) linked at 8259A. Since 8259A has been shutdown >> > > too early (by syscore_shutdown()), disable_nonboot_cpus() runs >> without >> > > timer interrupt, so it hangs and reboot fails. This patch call >> > > syscore_shutdown() a little later (after disable_nonboot_cpus()) to >> > > avoid reboot failure, this is the same way as poweroff does. >> > > >> > > BTW, add disable_nonboot_cpus() in kernel_halt() for consistency. >> > > >> > > Signed-off-by: Huacai Chen >> > > Cc: >> > >> > While I agree with the changes, I'm not sure if I'm the right >> maintainer, >> > as this isn't really PM code. >> > >> > Andrew, should I take this? >> >> Andrew is on vacation for a few weeks, so you might need to take this >> through your tree. > > OK > > But, it looks like we should actually disable interrupts on the remaining > CPU after we've called disable_nonboot_cpus() so that the > syscore_shutdown() > assumptions are satisfied which the patch doesn't do. > > Chen (I apologize if that's not the right part of your full name to use > here), > do you think that's not necessary and if so, then for what reason? Reboot and poweroff are both OK after I move syscore_shutdown(), I also don't know whether we should disable interrupts. Since you are the author of commit 40dc166c (PM / Core: Introduce struct syscore_ops for core subsystems PM), please tell me why syscore_shutdown() need interrupt disabled? (I just know that syscore_shutdown() will cause disable_nonboot_cpus() hang) BTW, Chen is my last name and you needn't worry about this. > > Rafael > > > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center. >