From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932326Ab2B2WIP (ORCPT ); Wed, 29 Feb 2012 17:08:15 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:48237 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932240Ab2B2WIN (ORCPT ); Wed, 29 Feb 2012 17:08:13 -0500 Date: Wed, 29 Feb 2012 16:08:09 -0600 From: Seth Forshee To: Grant Likely Cc: Matthew Garrett , 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: <20120229220809.GC20565@ubuntu-macmini> Mail-Followup-To: Grant Likely , 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> <20120229175327.GA20565@ubuntu-macmini> <20120229195042.GB20565@ubuntu-macmini> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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 Wed, Feb 29, 2012 at 03:23:20PM -0600, Grant Likely wrote: > On Wed, Feb 29, 2012 at 1:50 PM, Seth Forshee > wrote: > > On Wed, Feb 29, 2012 at 12:43:23PM -0600, Grant Likely wrote: > >> On Wed, Feb 29, 2012 at 11:53 AM, Seth Forshee > >> wrote: > >> > On Wed, Feb 29, 2012 at 11:46:39AM -0600, Grant Likely wrote: > >> >> On Wed, Feb 22, 2012 at 8:37 AM, Seth Forshee > >> >> wrote: > >> >> > Apple laptops with hybrid graphics have a device named gmux that > >> >> > controls the muxing of the LVDS panel between the GPUs as well as screen > >> >> > brightness. This driver adds support for the gmux device. Only backlight > >> >> > control is supported initially. > >> >> > > >> >> > Signed-off-by: Seth Forshee > >> >> > >> >> Works for me. > >> >> > >> >> Tested-by: Grant Likely > >> >> > >> >> Now I just need to figure out how to get the desktop backlight widget > >> >> to use gmux_backlight instead of acpi_video0... > >> > > >> > The easy way is to pass acpi_backlight=vendor to the kernel, then you > >> > won't have acpi_vidoe0. > >> > >> That did it, thanks.  I'm assume something is in the works to set it > >> up automatically? > > > > Not that I'm aware of. A number machines have this problem, that the > > standard ACPI backlight interfaces are implemented but don't work. This > > generally isn't detectable in software; with the Apples at least > > everything looks like it's working except that the brightness doesn't > > change (but not all Apple laptops are affected, so qurking based on > > manufacturer wouldn't work). All we're left with is DMI quirking, which > > isn't practical. Maybe we could add something so a platform driver can > > tell acpi_video that it knows the ACPI backlight doesn't work, but I > > think on some platforms that still is going to be based off of DMI > > information. > > blacklisting based on specific product name (ie. MacBookPro8,*) or > machine model is probably the best. It wouldn't be the first > blacklist in the linux kernel. I think the blacklist would have to be against specific product names. For example, the MacBook Pro 8,1 has a working acpi_video backlight and no gmux_backlight, the 8,2 has both but only gmux_backlight works, and I suspect the 8,3 is the same as the 8,2. We'd probably end up with an entry in the blacklist for every single model whose acpi_video backlight doesn't work, adding entries for each new generation of MacBooks. And if we start blacklisting Macs we'd have start doing it for other machines too, I guess. From what I've seen, open-ended blacklists like this get nacked pretty consistently nowadays. Seth