From mboxrd@z Thu Jan 1 00:00:00 1970 From: Seth Forshee Subject: Re: [PATCH v2] platform/x86: Add driver for Apple gmux device Date: Mon, 12 Mar 2012 10:40:00 -0500 Message-ID: <20120312154000.GC12322@ubuntu-macmini> 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> <20120312145701.GA12322@ubuntu-macmini> <20120312150717.GA13211@srcf.ucam.org> <20120312151852.GB12322@ubuntu-macmini> <20120312152224.GA13916@srcf.ucam.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from youngberry.canonical.com ([91.189.89.112]:38219 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755706Ab2CLPkH (ORCPT ); Mon, 12 Mar 2012 11:40:07 -0400 Content-Disposition: inline In-Reply-To: <20120312152224.GA13916@srcf.ucam.org> Sender: platform-driver-x86-owner@vger.kernel.org List-ID: To: Matthew Garrett Cc: platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org On Mon, Mar 12, 2012 at 03:22:24PM +0000, Matthew Garrett wrote: > On Mon, Mar 12, 2012 at 10:18:52AM -0500, Seth Forshee wrote: > > > Why do you presume it works under Windows? Boot camp installs a pile of > > drivers for Windows, one of those could be a driver for the backlight. I > > don't know either way. But it's pretty clear that MacOS is using the > > gmux for the backlight when it is present from the reverse engineering > > work done by others. > > The only reason to provide it at all is for Windows - it's never going > to be used under OS X. I'm not so sure. The MacBook Pro 8,1 and 8,2 seem to use the same BIOS implementation -- the version numbers and DSDTs are identical. The 8,1 has only Intel graphics, no gmux, and a working acpi_video0 backlight under Linux. The 8,2 has hybrid ATI/Intel, a gmux w/ working backlight control, and acpi_video0 does not work. So while I'm not sure, I can't rule out that the acpi_video backlight might be provided specifically for the 8,1 and that OS X is using it. Unfortunately I don't have an 8,1 that I can play with to try and work it out. Seth