From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757491Ab1ANNkC (ORCPT ); Fri, 14 Jan 2011 08:40:02 -0500 Received: from mail-ww0-f42.google.com ([74.125.82.42]:57114 "EHLO mail-ww0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756652Ab1ANNkA (ORCPT ); Fri, 14 Jan 2011 08:40:00 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mime-version:content-type :content-disposition:user-agent; b=ONQcYT/Sl+at/NVkS/029tjyYhmxoSSDbI+hCWM7ljM7fnyOBbZdQ3RcQYSN9c0dks +eUnNYD/JLEjZB9+01G6Lbc8BF1Zk1Iq3h81KbLzKfRKVYlYY4PwbbyXYs112t6PPJ8B qY/Q3gOXs1yRc0DXMZt8X85/tqIw1hJ595U98= Date: Fri, 14 Jan 2011 15:39:55 +0200 From: "Ahmed S. Darwish" To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: Randy Dunlap , x86@kernel.org, LKML Subject: Saving early panic() messages, to disk, using the BIOS Message-ID: <20110114133955.GA31019@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I'm facing some very early panics in latest -rc kernels. Vesafb is not even working, so only the very bottom of the stack trace is available. >>From an overall-design perspective, would a patch that saves such early panic messages to the hard-disk using real-mode BIOS calls be acceptable? That seems to be the only path to _fully_ capture such panic; this is a regular x86(-64) laptop with no serial ports or floppy disks. I'm in the lmode->pmode->rmode part now, but I thought it might be wise to quickly ask about such design mergeability before investing further effort. (There is an old set of patches in Randy's homepage that does something similar using floppy disks,[1] so it seems the basic idea is not that strange. I also do something similar in a hobby kernel of mine.[2]) thanks, [1] http://www.xenotime.net/linux/kmsgdump/ [1] http://gitorious.org/cute-os/cute/ -- Darwish