From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755652Ab2CLO5I (ORCPT ); Mon, 12 Mar 2012 10:57:08 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:37979 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752673Ab2CLO5F (ORCPT ); Mon, 12 Mar 2012 10:57:05 -0400 Date: Mon, 12 Mar 2012 09:57:01 -0500 From: Seth Forshee To: Matthew Garrett Cc: platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] platform/x86: Add driver for Apple gmux device Message-ID: <20120312145701.GA12322@ubuntu-macmini> Mail-Followup-To: Matthew Garrett , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org References: <1329424465-1211-1-git-send-email-seth.forshee@canonical.com> <1329921457-26887-1-git-send-email-seth.forshee@canonical.com> <20120312142126.GA11969@srcf.ucam.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120312142126.GA11969@srcf.ucam.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 12, 2012 at 02:21:26PM +0000, Matthew Garrett wrote: > apple_bl probably needs some matching work to disable itself if there's > a gmux present? Otherwise, this looks good. How do you suggest doing this? The tricky point is that the gmux object can be present in ACPI when the gmux hardware isn't really present (which is what the version check really does, verifies the hardware is actually there). So apple_bl can't just look for the ACPI object; it needs to either communicate with apple-gmux or duplicate some of its logic. We also have the problem of gmux_backlight versus acpi_video. On most machines with a gmux the acpi_video backlight interface is present but just doesn't work. This problem isn't just limited to Apples. I'm of the opinion that we need a more generalized solution for arbitrating between the backlight interfaces present on a given machine, but I haven't had a chance to really think about what that would look like. Seth