Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753667AbaDDPiq (ORCPT ); Fri, 4 Apr 2014 11:38:46 -0400 Received: from mail-ve0-f178.google.com ([209.85.128.178]:52859 "EHLO mail-ve0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753246AbaDDPio (ORCPT ); Fri, 4 Apr 2014 11:38:44 -0400 MIME-Version: 1.0 In-Reply-To: <20140404151203.GA12370@srcf.ucam.org> References: <533D7C4F.4010504@zytor.com> <533D7C93.7080105@zytor.com> <20140403113921.23dceb75@gandalf.local.home> <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> Date: Fri, 4 Apr 2014 08:38:42 -0700 X-Google-Sender-Auth: mp9_8Ex-7p9K_hDt_odmvU45ZnE Message-ID: Subject: Re: [BUG] x86: reboot doesn't reboot From: Linus Torvalds To: Matthew Garrett Cc: "Li, Aubrey" , "H. Peter Anvin" , Steven Rostedt , Ingo Molnar , LKML , Thomas Gleixner Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 4, 2014 at 8:12 AM, Matthew Garrett wrote: > > Production hardware should never require CF9. That's total BS. The fact is, we may be doing something wrong, but ACPI fails on a *lot* of systems. A huge swath of Dell machines in particular for some reason (laptops, desktops, _and_ now there's tablet reports). And EFI isn't even in the running. The keyboard controller is sadly unreliable too, although I really don't understand why. Even when a legacy keyboard controller exists (which isn't as universal as you'd think, even though the *hardware* is pretty much guaranteed to be there in the chipset, it can be disabled) there seem to be machines where the reset line isn't hooked up. Don't ask me why. Same goes for the triple fault failure case. End result: there's a *lot* of machines that seem to want the PCI or legacy BIOS reboot. And it has absolutely _zero_ to do with "production hardware". It would be interesting if somebody can figure out *exactly* what Windows does, because the fact that a lot of Dell machines need quirks almost certainly means that it's _us_ doing something wrong. Dell doesn't generally do lots of fancy odd things. I pretty much guarantee it's because we've done something odd that Windows doesn't do. Anyway, claiming that the PCI method shouldn't be needed is living in some kind of dream-land. The fact is, all the other methods are equally broken, or more so. Linus -- 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/