Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760766Ab3GaRqJ (ORCPT ); Wed, 31 Jul 2013 13:46:09 -0400 Received: from mail-lb0-f171.google.com ([209.85.217.171]:61924 "EHLO mail-lb0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760527Ab3GaRqG (ORCPT ); Wed, 31 Jul 2013 13:46:06 -0400 MIME-Version: 1.0 In-Reply-To: <20130731140010.GA24560@srcf.ucam.org> References: <1375125658-1223-1-git-send-email-felipe.contreras@gmail.com> <3453253.oZLO1ChPbL@vostro.rjw.lan> <37178266.QXgbv9rq0i@vostro.rjw.lan> <20130731051421.GA15766@srcf.ucam.org> <20130731140010.GA24560@srcf.ucam.org> Date: Wed, 31 Jul 2013 12:46:04 -0500 Message-ID: Subject: Re: [REGRESSION/PATCH] acpi: blacklist win8 OSI for ASUS Zenbok Prime UX31A From: Felipe Contreras To: Matthew Garrett Cc: "Rafael J. Wysocki" , Aaron Lu , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, Len Brown , Linus Torvalds Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1251 Lines: 29 On Wed, Jul 31, 2013 at 9:00 AM, Matthew Garrett wrote: > On Wed, Jul 31, 2013 at 06:32:47AM -0500, Felipe Contreras wrote: >> On Wed, Jul 31, 2013 at 12:14 AM, Matthew Garrett wrote: >> > There's no mechanism for an OS to know whether or not a firmware >> > implementation will actually turn the backlight off at 0, so there's no >> > way the OS can define the lowest backlight state as anything other than >> > "May or may not turn the screen off". >> >> Yes there is; quirks. > > We aren't going to maintain a quirk list in order to support a guarantee > that was never made. "0" as a backlight level has potentially meant > "screen off" since the interface was first introduced. That doesn't change the fact that you were wrong, and there *is* actually a way. The fact that you don't want to go there doesn't mean it's not there. Here's another: device tree. There are ways to provide a consistent backlight interface to user-space. -- Felipe Contreras -- 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/