Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755081Ab1CKBaI (ORCPT ); Thu, 10 Mar 2011 20:30:08 -0500 Received: from smarthost1.greenhost.nl ([195.190.28.78]:52450 "EHLO smarthost1.greenhost.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754592Ab1CKBaG (ORCPT ); Thu, 10 Mar 2011 20:30:06 -0500 Message-ID: <8e40e6468e9cf03138a512550f1e519e.squirrel@webmail.greenhost.nl> In-Reply-To: References: <20110216192658.GA7225@blimp.localdomain> <20110217221329.GA3332@x61.home> <3f792aaf90cf0b3d49be21baa2682d5d.squirrel@webmail.greenhost.nl> <20110222130440.21a27714@jbarnes-desktop> <20110222223120.GA3567@x61.home> <3e6f092bd0aa54fd6b9eb524f6c87ecf.squirrel@webmail.greenhost.nl> <1a06e2711df021a802d609ad1a75db17.squirrel@webmail.greenhost.nl> Date: Fri, 11 Mar 2011 02:30:04 +0100 (CET) Subject: Re: [PATCH] drm/i915: Revive combination mode for backlight control From: "Indan Zupancic" To: "Keith Packard" Cc: "Takashi Iwai" , "Linux Kernel Mailing List" , "DRI mailing list" , "Alex Riesen" , "Tino Keitel" , "Linus Torvalds" , stable@kernel.org User-Agent: SquirrelMail/1.4.17 MIME-Version: 1.0 Content-Type: text/plain;charset=UTF-8 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-Spam-Score: 0.1 X-Scan-Signature: 938925967a2432a0d8c7279c30be63be Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1347 Lines: 36 On Thu, March 10, 2011 20:36, Keith Packard wrote: > On Thu, 10 Mar 2011 14:02:12 +0100, Takashi Iwai wrote: >> + val &= ~1; > > The reason for this is that some ancient platforms wire this bit to > be "go to max backlight", or at least that's why this was in the 2D > driver from which this code was derived. If that is the case, then shouldn't it be at the end, after val *= lbpc? I know it doesn't make much difference, as multiplying with an even number always gives an even result, but it would make the intention clearer and give a more precise result. What about gen 3? Does it support combination mode too? If you can confirm that there are no gen 2 systems with ASLE support, we can remove the gen 2 check and only touch the PWM register, as the ASLE code is the only one that changes the brightness. The panel code only saves and restores it, and LBPC is saved and restored by the BIOS already. Then those weird gen 2 quirks can be removed. (Something for 2.6.39 perhaps.) It's sad that something as simple as backlight control needs so much code. Greetings, Indan -- 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/