Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754442AbaDDReh (ORCPT ); Fri, 4 Apr 2014 13:34:37 -0400 Received: from mail-wi0-f174.google.com ([209.85.212.174]:56559 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754062AbaDDRef (ORCPT ); Fri, 4 Apr 2014 13:34:35 -0400 Date: Fri, 4 Apr 2014 19:34:31 +0200 From: Ingo Molnar To: Matthew Garrett Cc: "H. Peter Anvin" , "Li, Aubrey" , Steven Rostedt , Linus Torvalds , LKML , Thomas Gleixner Subject: Re: [BUG] x86: reboot doesn't reboot Message-ID: <20140404173431.GA25173@gmail.com> References: <533D8516.1040803@zytor.com> <20140403121314.246b03a7@gandalf.local.home> <533DED74.6050202@linux.intel.com> <20140403194018.7c67aec7@gandalf.local.home> <533DF455.4040908@linux.intel.com> <533DF8D2.9060508@zytor.com> <533E0A94.5040007@linux.intel.com> <20140404151203.GA12370@srcf.ucam.org> <533ECC2C.6090505@zytor.com> <20140404153634.GA14519@srcf.ucam.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140404153634.GA14519@srcf.ucam.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Matthew Garrett wrote: > On Fri, Apr 04, 2014 at 08:13:48AM -0700, H. Peter Anvin wrote: > > On 04/04/2014 08:12 AM, Matthew Garrett wrote: > > > On Fri, Apr 04, 2014 at 09:27:48AM +0800, Li, Aubrey wrote: > > > > > >> The current situation is, > > >> - we have one(do we know more?) preproduction machine hangs by CF9. > > >> - We have more than one(could be thousand known) production machine > > >> works by CF9. > > > > > > Production hardware should never require CF9. > > > > > > > There are a lot of things that shouldn't be. > > Windows doesn't hit CF9, and production hardware is always tested with > Windows, so. [...] So why the hell does the reboot function comment claim that the Windows reboot sequence (which is the de facto hardware standard) uses 0xcf9: /* * Windows compatible x86 hardware expects the following on reboot: * * 1) If the FADT has the ACPI reboot register flag set, try it * 2) If still alive, write to the keyboard controller * 3) If still alive, write to the ACPI reboot register again * 4) If still alive, write to the keyboard controller again * 5) If still alive, call the EFI runtime service to reboot * 6) If still alive, write to the PCI IO port 0xCF9 to reboot * 7) If still alive, inform BIOS to do a proper reboot * ?? Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/