From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261316AbVFDK5Q (ORCPT ); Sat, 4 Jun 2005 06:57:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261318AbVFDK5P (ORCPT ); Sat, 4 Jun 2005 06:57:15 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:59296 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id S261316AbVFDK5L (ORCPT ); Sat, 4 Jun 2005 06:57:11 -0400 Message-ID: <1117882628.42a1890479c23@imap.linux.ibm.com> Date: Sat, 4 Jun 2005 06:57:08 -0400 From: Vivek Goyal To: Alan Stern Cc: linux kernel mailing list , greg@kroah.com, Fastboot mailing list , Morton Andrew Morton , "Eric W. Biederman" 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: 9.182.63.159 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Quoting Alan Stern : > On Fri, 3 Jun 2005, Vivek Goyal wrote: > > > In previous conversations, Alan Stern had raised the issue of console > also > > not working if interrupts are disabled on all the devices. I am not sure > > but this should be working at least for serial consoles and vga text > consoles. > > May be sufficient to capture the dump. > > This isn't an issue for x86. It affects other architectures, in which the > system console is managed during the early stages of booting by the > platform firmware. I suppose serial consoles would always work. > Hi Alan, I know very little about consoles and their working. I had a question. Even if console is being managed by platform firmware, in initial states of booting, does it require interrupts to be enabled at VGA contorller (at least for the simple text mode). I was quickly browsing through drivers/video/console/vgacon.c and did not look like that this console driver needed interrupts to be enabled at the controller. Anyway, looks like serial consoles will always work. So at least this can be done for kdump case (CONFIG_CRASH_DUMP) and not generic kernel. Or, as I mentioned in previous mail, while pre-loading capture kernel, pass a command line parameter containing pci dev id of console and capture kernel does not disable interrupts on this console. Thanks Vivek