From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH]: ACPI: Skip the power state check in power transition Date: Thu, 14 May 2009 11:56:27 +0100 Message-ID: <20090514105626.GA17294@srcf.ucam.org> References: <1242106060.3773.216.camel@localhost.localdomain> <200905120857.40058.bjorn.helgaas@hp.com> <1242184384.3773.241.camel@localhost.localdomain> <20090513130803.GA27522@srcf.ucam.org> <1242265659.3773.428.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cavan.codon.org.uk ([93.93.128.6]:46436 "EHLO vavatch.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752870AbZENK4c (ORCPT ); Thu, 14 May 2009 06:56:32 -0400 Content-Disposition: inline In-Reply-To: <1242265659.3773.428.camel@localhost.localdomain> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: yakui_zhao Cc: Bjorn Helgaas , "lenb@kernel.org" , "linux-acpi@vger.kernel.org" On Thu, May 14, 2009 at 09:47:39AM +0800, yakui_zhao wrote: > On Wed, 2009-05-13 at 21:08 +0800, Matthew Garrett wrote: > > The default behaviour should be to be compatible with Windows, > > regardless of what the spec says. There's an argument for providing a > > strict interpretation of the spec for testing purposes, but I don't > > see > > any reason for it to be split up into dozens of individual kernel > > parameters > The ACPI 1.0 spec is followed by windows XP. And the power state is not > checked in power transition under windows XP. > But we don't know whether it is still skipped on the new version > windows.(For example: Windows 7). > > If the module param is removed, we must delete the source code related > with power state check. And if the power state is checked in power > transition on windows 7, what we should do? It is not reasonable to add > them again. If Windows 7 changes the behaviour then the correct approach is to key this behaviour on whether the system firmware requests the Windows 7 OSI string. The code can be #if 0ed out until then, or placed under an acpi.strict kernel option that turns on all standards-compliant but windows-incompatible code. > Maybe it is better to determine whether the power state check is skipped > in power transition. We have a stated policy that Linux will default to being Windows compatible. You've demonstrated that in this case Linux isn't Windows compatible, which means that it's a bug. The correct behaviour for Linux here is to ignore the _STA value (or, indeed, not to call _STA at all in this path). -- Matthew Garrett | mjg59@srcf.ucam.org