From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752770Ab0FVSbE (ORCPT ); Tue, 22 Jun 2010 14:31:04 -0400 Received: from cpoproxy2-pub.bluehost.com ([67.222.39.38]:56050 "HELO cpoproxy2-pub.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752002Ab0FVSbA (ORCPT ); Tue, 22 Jun 2010 14:31:00 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=virtuousgeek.org; h=Received:Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References:X-Mailer:Mime-Version:Content-Type:Content-Transfer-Encoding:X-Identified-User; b=MRa4iXZtGRjMHIC66M4igyfgo8UXARNkBDNp9/UHYLTo865dNna/OyCR+ux8OeBpLs9UqMn6W5NGiyB92+/7jjges7skZ+ZUKu2rFpHQSQ98KMP8rQ7t3u7QLezzfTS/; Date: Tue, 22 Jun 2010 11:29:08 -0700 From: Jesse Barnes To: "Rafael J. Wysocki" Cc: Matthew Garrett , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ACPI: Disable ASPM if the platform won't provide _OSC control for PCIe Message-ID: <20100622112908.4122ceb2@virtuousgeek.org> In-Reply-To: <201006222017.30023.rjw@sisk.pl> References: <1277220343-25168-1-git-send-email-mjg@redhat.com> <201006222017.30023.rjw@sisk.pl> X-Mailer: Claws Mail 3.7.5 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Identified-User: {10642:box514.bluehost.com:virtuous:virtuousgeek.org} {sentby:smtp auth 75.110.194.140 authed with jbarnes@virtuousgeek.org} Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 22 Jun 2010 20:17:29 +0200 "Rafael J. Wysocki" wrote: > On Tuesday, June 22, 2010, Matthew Garrett wrote: > > The PCI SIG documentation for the _OSC OS/firmware handshaking interface > > states: > > > > "If the _OSC control method is absent from the scope of a host bridge > > device, then the operating system must not enable or attempt to use any > > features defined in this section for the hierarchy originated by the host > > bridge." > > > > The obvious interpretation of this is that the OS should not attempt to use > > PCIe hotplug, PME or AER - however, the specification also notes that an > > _OSC method is *required* for PCIe hierarchies, and experimental validation > > with An Alternative OS indicates that it doesn't use any PCIe functionality > > if the _OSC method is missing. That arguably means we shouldn't be using > > MSI or extended config space, but right now our problems seem to be limited > > to vendors being surprised when ASPM gets enabled on machines when other > > OSs refuse to do so. So, for now, let's just disable ASPM if the _OSC > > method doesn't exist or refuses to hand over PCIe capability control. > > > > Signed-off-by: Matthew Garrett > > Acked-by: Rafael J. Wysocki Applied to my linux-next branch, thanks. -- Jesse Barnes, Intel Open Source Technology Center