From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH 10/10] x86, ACPI: default to reboot via ACPI (again) Date: Tue, 11 Nov 2008 10:26:07 -0800 Message-ID: <4919CE3F.4010008@zytor.com> References: <007e7d616a5d1c2e16ad627d03f8b97799445e71.1226032943.git.len.brown@intel.com> <200811080930.21462.arvidjaar@mail.ru> <200811081050.25477.arvidjaar@mail.ru> <20081108115956.GE8354@elte.hu> <4916B38B.7050905@redhat.com> <4916B4DB.90602@zytor.com> <20081110083938.GD22392@elte.hu> <4917F6A9.3020408@redhat.com> <20081110090241.GH22392@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from terminus.zytor.com ([198.137.202.10]:45802 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751455AbYKKS1Q (ORCPT ); Tue, 11 Nov 2008 13:27:16 -0500 In-Reply-To: <20081110090241.GH22392@elte.hu> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Ingo Molnar Cc: Avi Kivity , "Eric W. Biederman" , Andrey Borzenkov , Len Brown , linux-acpi@vger.kernel.org, Len Brown , Thomas Gleixner , Eduardo Habkost , Andrew Morton Ingo Molnar wrote: > > well then we could insert CF9 to before the triple fault, and solve > some of the problems as well, without unnecessary risks. > > This is a separate patch from ACPI reboot itself, naturally. > This is a pretty good point. There is extremely low risk of being something at port CF9 that is something other than the reset register. It may not be there, but if it isn't, the worst thing that happened is we confused a device right before reset. Even better if we condition the port CF9 write on existence a PCI bus (or even more specifically PCI Configuration Method #1 or #2). Port CF9 is extremely unlikely to exist on a machine without a PCI bus, and extremely unlikely to conflict with anything else on a machine with a PCI bus. -hpa