From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753732AbYIDOgA (ORCPT ); Thu, 4 Sep 2008 10:36:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751481AbYIDOfx (ORCPT ); Thu, 4 Sep 2008 10:35:53 -0400 Received: from mx1.redhat.com ([66.187.233.31]:49486 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751340AbYIDOfx (ORCPT ); Thu, 4 Sep 2008 10:35:53 -0400 Message-ID: <48BFF0C0.7060208@redhat.com> Date: Thu, 04 Sep 2008 10:29:20 -0400 From: Prarit Bhargava User-Agent: Thunderbird 2.0.0.16 (X11/20080707) MIME-Version: 1.0 To: Peter Zijlstra CC: linux-kernel@vger.kernel.org, arozansk@redhat.com, dzickus@redhat.com, Thomas.Mingarelli@hp.com, ak@linux.intel.com, mingo@elte.hu Subject: Re: [PATCH RFC] NMI Re-introduce un[set]_nmi_callback References: <20080904130048.31841.3329.sendpatchset@prarit.bos.redhat.com> <1220535463.8609.223.camel@twins> In-Reply-To: <1220535463.8609.223.camel@twins> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Why is the DIE_NMIWATCHDOG notifier not sufficient for this driver? > > Peter -- good question. The HP systems with this HW will use the hpwdt driver in place of the default nmi watchdog. When the HW detects a problem, the HW will generate a single NMI that the driver will handle. The driver doesn't want the NMI to be rejected due to a reason code. I'm sure that Thomas Mingarelli, who is cc'd, can provide further details. From our quick conversation as well, you raised an interesting point about oprofile, kgdb, and other subsystems that use the NMI notifier chains -- they may be impacted by the NMI callback. Don (dzickus) or Aris, do you have any thoughts on how to get around the second issue? We could check to see if anything is registered on the notifier chain and the fail to register the callback. P.