From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752758Ab1HIPDS (ORCPT ); Tue, 9 Aug 2011 11:03:18 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:44407 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750850Ab1HIPDR (ORCPT ); Tue, 9 Aug 2011 11:03:17 -0400 Date: Tue, 9 Aug 2011 17:02:24 +0200 From: Ingo Molnar To: Bruno Friedmann Cc: "H. Peter Anvin" , Matthew Garrett , Mel Gorman , tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: Add reboot quirk for Dell Precision M4600 Message-ID: <20110809150224.GF28228@elte.hu> References: <20110727125651.GH3010@suse.de> <20110806065635.GE13220@elte.hu> <20110806153003.GA1238@srcf.ucam.org> <4E40119A.5010803@zytor.com> <4E41197D.30209@ioda-net.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E41197D.30209@ioda-net.ch> User-Agent: Mutt/1.5.21 (2010-09-15) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Bruno Friedmann wrote: > 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. Didn't hpa suggest reboot=kbd? Thanks, Ingo