From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752123AbYA1FKy (ORCPT ); Mon, 28 Jan 2008 00:10:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750764AbYA1FKo (ORCPT ); Mon, 28 Jan 2008 00:10:44 -0500 Received: from smtp2.linux-foundation.org ([207.189.120.14]:54842 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750726AbYA1FKn (ORCPT ); Mon, 28 Jan 2008 00:10:43 -0500 Date: Sun, 27 Jan 2008 21:10:13 -0800 From: Andrew Morton To: Matthew Garrett Cc: Len Brown , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [PATCH] Rationalise ACPI backlight implementation Message-Id: <20080127211013.1ddaa6a1.akpm@linux-foundation.org> In-Reply-To: <20080128012549.GA24166@srcf.ucam.org> References: <20071226020325.GA21099@srcf.ucam.org> <200801241644.49114.lenb@kernel.org> <20080126220045.b93db7c9.akpm@linux-foundation.org> <20080128012549.GA24166@srcf.ucam.org> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 28 Jan 2008 01:25:50 +0000 Matthew Garrett wrote: > On Sat, Jan 26, 2008 at 10:00:45PM -0800, Andrew Morton wrote: > > - Create a new /sys node with a new name which has the new semantics. > > The semantics are the same as they always have been - values between 0 > and max_brightness are valid values. If you've made assumptions about > what max_brightness is, then that's a bug in the userspace application > rather than a change in the semantics of the interface. > WTH? My (utterly comedic chase-crap-around-the-tree) brightness script was: ( 0 sh -c "echo $1 > /proc/acpi/sony/brightness" 0 sh -c "echo $1 > /proc/acpi/sony/brightness_default" 0 sh -c "echo $1 > /sys/class/backlight/sony/brightness" 0 sh -c "echo $1 > /sys/class/backlight/thinkpad_screen/brightness" ) 2>/dev/null And yes, I had an rc.local command which assumed that 7 (later 8) is max brightness. You cannot seriously tell me that if we are to change this range from 0-8 up to 0-100 then this is not a backwards-incompatible change in semantics. My /sys/class/backlight/ directory is presently empty. Rather than trying to find out why, I think I'll just collapse in laughter. Guys, sort it out, please.