From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH] Add DMI quirk for Intel DP55KG mainboard Date: Wed, 6 Jan 2010 20:29:18 +0000 Message-ID: <20100106202918.GA22957@srcf.ucam.org> References: <20100104162114.GA30113@percival.namespace.at> <4B4225B3.8070705@zytor.com> <20100104174558.158cd512@infradead.org> <20100106143640.GB13984@srcf.ucam.org> <20100106193608.GA21447@srcf.ucam.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cavan.codon.org.uk ([93.93.128.6]:50221 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932554Ab0AFUaZ (ORCPT ); Wed, 6 Jan 2010 15:30:25 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Len Brown Cc: Arjan van de Ven , "H. Peter Anvin" , Christian Hofstaedtler , x86@kernel.org, Linux Kernel Mailing List , bruce.w.allan@intel.com, Thomas Gleixner , Justin Piszcz , linux-acpi@vger.kernel.org, Venkatesh Pallipadi On Wed, Jan 06, 2010 at 03:22:30PM -0500, Len Brown wrote: > I've looked at _OSI use in over a hundred DSDTs and never > seen run-time re-configuration of reset support. The point isn't that the firmware changes its behaviour - the point is that the OS does. > I do not think the BIOS has a run-time decision to make here. > If a box is designed to support Windows XP and newer, it is > likely that ACPI_RESET is simply valid and XP blindly uses it. > If reset fails, the box doesn't pass WHQL and the box is fixed. > If W2K is run on that box, ACPI_RESET is still valid, just that > W2K chooses to not write to it. And if ACPI_RESET is set but untested (because 2000 never used it)? > We can't rely on blind use of _OSI to mean "new enough", since > it was supported back in W2K era. That means we have to parse > the OSI strings. But what happens when a BIOS writer decides to > evaluate _OSI("Windows Future") without evaluating any of the > old strings we know about? We would disable ACPI reset on such > a future box? Potentially, yes. But since such a machine would clearly expect to be treated as "Windows Future", we'd be running it in an untested configuration anyway. -- Matthew Garrett | mjg59@srcf.ucam.org