From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753373Ab1HIMBi (ORCPT ); Tue, 9 Aug 2011 08:01:38 -0400 Received: from smtp.ioda.net ([87.98.140.96]:42937 "EHLO smtp.ioda.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752641Ab1HIMBh (ORCPT ); Tue, 9 Aug 2011 08:01:37 -0400 Message-ID: <4E41197D.30209@ioda-net.ch> Date: Tue, 09 Aug 2011 13:26:53 +0200 From: Bruno Friedmann Organization: Ioda-Net =?UTF-8?B?U8Ogcmw=?= User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:6.0) Gecko/20110729 Thunderbird/6.0 MIME-Version: 1.0 To: "H. Peter Anvin" CC: Matthew Garrett , Ingo Molnar , Mel Gorman , tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: Add reboot quirk for Dell Precision M4600 References: <20110727125651.GH3010@suse.de> <20110806065635.GE13220@elte.hu> <20110806153003.GA1238@srcf.ucam.org> <4E40119A.5010803@zytor.com> In-Reply-To: <4E40119A.5010803@zytor.com> X-Enigmail-Version: 1.3a1pre Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/08/2011 06:40 PM, H. Peter Anvin wrote: > On 08/06/2011 10:30 AM, Matthew Garrett wrote: >> On Sat, Aug 06, 2011 at 08:56:35AM +0200, Ingo Molnar wrote: >>> Weird - ACPI is the default Windows method of reboot - how come it >>> does not work on that box? Does Windows work around this specific >>> machine (unlikely), or is our ACPI boot sequence not 100% compatible >>> with the Windows method (more likely IMO)? >> >> The ACPI reboot method on these machines hits the keyboard controller >> rather than PCI, which is unusual. What I suspect is that the write >> triggers some SMM or EC code that's making assumptions about system >> state, and we're not quite identical. Bouncing on the keyboard >> controller from userspace with init=/bin/bash wedges in the same way. >> > > I have a vague suspicion that Windows might have a meta-quirk for this > class of machines, i.e. if the ACPI reboot method, say, points at the > keyboard controller or points at the "PCI" reboot port then it actually > uses its own special-purpose routines rather than general routines. It > would be extremely interesting to know if "reboot=kbd" works on these boxen. > > -hpa > Test done with reboot=pci and unfortunately doesn't work. -- Bruno Friedmann Ioda-Net Sàrl www.ioda-net.ch openSUSE Member & Ambassador GPG KEY : D5C9B751C4653227 irc: tigerfoot