Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751364Ab3IZFPX (ORCPT ); Thu, 26 Sep 2013 01:15:23 -0400 Received: from mail-pb0-f45.google.com ([209.85.160.45]:45880 "EHLO mail-pb0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751030Ab3IZFPV (ORCPT ); Thu, 26 Sep 2013 01:15:21 -0400 Date: Thu, 26 Sep 2013 13:15:53 +0800 From: Aaron Lu To: "Rafael J. Wysocki" Cc: linux-acpi@vger.kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Vetter , Matthew Garrett , Seth Forshee , Lee Chun-Yi , Richard Purdie , Igor Gnatenko , Yves-Alexis Perez , Felipe Contreras , Henrique de Moraes Holschuh , Jani Nikula , Ben Jencks , Steven Newbury , James Hogan , Kamal Mostafa , Joerg Platte , Kalle Valo , Martin Steigerwald , =?iso-8859-1?Q?J=F6rg?= Otte , Mike Galbraith Subject: Re: [PATCH v3 3/4] ACPI / video: Do not register backlight if win8 and native interface exists Message-ID: <20130926051552.GB14158@aaronlu.linux.com> References: <1380016052-15315-1-git-send-email-aaron.lu@intel.com> <1380016052-15315-4-git-send-email-aaron.lu@intel.com> <2597446.Ay4U1OH2zV@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2597446.Ay4U1OH2zV@vostro.rjw.lan> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1358 Lines: 28 On Wed, Sep 25, 2013 at 07:53:13PM +0200, Rafael J. Wysocki wrote: > On Tuesday, September 24, 2013 05:47:31 PM Aaron Lu wrote: > > According to Matthew Garrett, "Windows 8 leaves backlight control up > > to individual graphics drivers rather than making ACPI calls itself. > > There's plenty of evidence to suggest that the Intel driver for > > Windows [8] doesn't use the ACPI interface, including the fact that > > it's broken on a bunch of machines when the OS claims to support > > Windows 8. The simplest thing to do appears to be to disable the > > ACPI backlight interface on these systems". > > > > So for Win8 systems, if there is native backlight control interface > > registered by GPU driver, ACPI video will not register its own. For > > users who prefer to keep ACPI video's backlight interface, the existing > > kernel cmdline option acpi_backlight=video can be used. > > I think the idea is to use the aggressive default for now and we can switch the > default back to the current behavior before the merge window in case there are > too many problems with it? Yes I think so. Thanks, Aaron -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/