From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lu Subject: Re: [PATCH] ACPI: Disable Windows 8 compatibility for some Lenovo ThinkPads Date: Mon, 22 Apr 2013 22:07:32 +0800 Message-ID: <51754424.6040203@intel.com> References: <1360599681-24781-1-git-send-email-seth.forshee@canonical.com> <9174410.cA7eiWOPcn@vostro.rjw.lan> <5175055F.9000600@intel.com> <1587525.URWXxEIA21@vostro.rjw.lan> <517528E5.7030105@intel.com> <20130422130600.GA31365@thinkpad-t410> <51753DB0.9010703@intel.com> <20130422135651.GB31365@thinkpad-t410> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pa0-f42.google.com ([209.85.220.42]:55110 "EHLO mail-pa0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754218Ab3DVOHl (ORCPT ); Mon, 22 Apr 2013 10:07:41 -0400 Received: by mail-pa0-f42.google.com with SMTP id kq13so3644737pab.1 for ; Mon, 22 Apr 2013 07:07:41 -0700 (PDT) In-Reply-To: <20130422135651.GB31365@thinkpad-t410> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Seth Forshee Cc: "Rafael J. Wysocki" , Ben Jencks , Len Brown , linux-acpi@vger.kernel.org, joeyli , Matthew Garrett On 04/22/2013 09:56 PM, Seth Forshee wrote: > On Mon, Apr 22, 2013 at 09:40:00PM +0800, Aaron Lu wrote: >> On 04/22/2013 09:06 PM, Seth Forshee wrote: >>> On Mon, Apr 22, 2013 at 08:11:17PM +0800, Aaron Lu wrote: >>>> On 04/22/2013 07:51 PM, Rafael J. Wysocki wrote: >>>>> I suppose we need to blacklist them to start with. I wouldn't like to apply >>>>> any general changes before we know how many different systems are affected by >>>>> this particular issue. >>>> >>>> I totally agree. >>> >>> Are you sure that all of these machines have an alternate interface for >>> userspace to change the brightness? I know that I've got a non-Lenovo >>> machine with nVidia graphics for which nouveau exposes no backlight >> >> What's the problem with this system then? The same as the thinkpads in >> bug 51231? > > There's no problem with that system; it has another working backlight > interface. I'm only mentioning it to demonstrate that taking away the > ACPI interface could leave some machines without any backlight control > mechanism that Linux currently supports. I think we just need take away the ACPI interface for these known broken systems for now, that would require: check if we are in win8 mode, if so, disable acpi video interface for these known broken systems. I think video_detect_dmi_table is the proper place to do this. -Aaron