From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261835AbVFGL4p (ORCPT ); Tue, 7 Jun 2005 07:56:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261839AbVFGL4p (ORCPT ); Tue, 7 Jun 2005 07:56:45 -0400 Received: from e31.co.us.ibm.com ([32.97.110.129]:31617 "EHLO e31.co.us.ibm.com") by vger.kernel.org with ESMTP id S261835AbVFGL4m (ORCPT ); Tue, 7 Jun 2005 07:56:42 -0400 Message-ID: <1118145394.42a58b728a15a@imap.linux.ibm.com> Date: Tue, 7 Jun 2005 07:56:34 -0400 From: Vivek Goyal To: Grant Grundler Cc: greg@kroah.com, linux kernel mailing list , Fastboot mailing list , Morton Andrew Morton , "Eric W. Biederman" , Bodo Eggert <7eggert@gmx.de>, Dipankar Sarma , stern@rowland.harvard.edu, awilliam@fc.hp.com, bjorn.helgaas@hp.com Subject: Re: [RFC/PATCH] Kdump: Disabling PCI interrupts in capture kernel MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT User-Agent: Internet Messaging Program (IMP) 3.2.7 X-Originating-IP: 9.184.230.205 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Quoting Grant Grundler : > On Mon, Jun 06, 2005 at 11:07:17PM -0400, Vivek Goyal wrote: > > So even if interrupts are disabled on PCI-PCI bridge, interrupts > generated > > by PCI devices on secondary bus are not blocked and I hope device > should > > be working fine. > > How did you plan on disabling interrupts? > Did you see the MSI discussion that going on now in linux-pci mailing list? I am following the discussion now. Thanks. I am planning to disable only leagacy shared interrupts (irq pin assertion/INTx emulation) because shared interrupts are a problem. MSI are not shared but I am not sure can they lead to any other problem. > > > But at the same time kdump kernels are not supposed to > > do a great deal except capture and save the dump. > > I'd think you want to stop DMA for all devices. > Just to prevent them from messing more with memory > that you want to dump - ie get a consistent snapshot. > Leaving VGA devices alone should be safe. > May be at some point of time. > > Disabling interrupts at PCI level should increase the reliability of > capturing > > the dump on newer machines with hardware compliant with PCI 2.3 or higher. > > > *lots* of PCI devices predate PCI2.3. Possibly even the majority. Ya, Some other solution is needed for hardware predating PCI2.3. May be Eric's suggestion of polling the hardware. Thanks Vivek