From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751987AbbCNT7A (ORCPT ); Sat, 14 Mar 2015 15:59:00 -0400 Received: from mail-pd0-f171.google.com ([209.85.192.171]:36031 "EHLO mail-pd0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751333AbbCNT67 (ORCPT ); Sat, 14 Mar 2015 15:58:59 -0400 From: Jason Ekstrand X-Google-Original-From: Jason Ekstrand To: linux-kernel@vger.kernel.org Cc: Jason Ekstrand Subject: RE: [PATCH] ACPI: Adjust the return value of _REV on x86 Date: Sat, 14 Mar 2015 12:58:51 -0700 Message-Id: <1426363131-14530-1-git-send-email-jason.ekstrand@intel.com> X-Mailer: git-send-email 2.3.2 In-Reply-To: <1426150247-18309-1-git-send-email-matthew.garrett@nebula.com> References: <1426150247-18309-1-git-send-email-matthew.garrett@nebula.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jason Ekstrand On Wed, 11 Mar 2015 22:50:47, Matthew Garrett wrote: > The ACPI spec describes _REV as: > > "This predefined object evaluates to the revision of the ACPI Specification > that the specified \_OS implements" > > We've been assuming that this should increment as ACPICA gains support for > new versions of the spec. Unfortunately, Windows always reports "2" for this > value and vendors are now using this as a means to tell whether a system is > running Windows or Linux. From an HP Envy 15: > > If (LOr (LEqual (_REV, 0x03), LEqual (_REV, 0x05))) > > From a Dell XPS 13: > > If ((_REV == 0x05)) I can confirm that on my 2015 Dell XPS 13, this patch fixes both the audio and suspend/resume. I'm running a build of Linus' master branch as of some time this morning. Without this patch applied I have no audio and suspend fails leaving the system unresponsive but the keyboard light still on and the fan running indefinitely. With this patch, I get audio and suspend/resume works normally. --Jason Ekstrand