From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755143Ab1CMQRf (ORCPT ); Sun, 13 Mar 2011 12:17:35 -0400 Received: from kroah.org ([198.145.64.141]:41497 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754738Ab1CMQRY (ORCPT ); Sun, 13 Mar 2011 12:17:24 -0400 Date: Sun, 13 Mar 2011 09:17:53 -0700 From: Greg KH To: Nikolai Kondrashov Cc: Matthew Garrett , Randy Dunlap , linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org Subject: Re: [PATCH] Platform: add Samsung Laptop platform driver Message-ID: <20110313161752.GC10718@kroah.com> References: <20110310180959.GA26927@kroah.com> <4D793D05.3070908@gmail.com> <20110310211519.GA11862@kroah.com> <4D79CB47.2030405@gmail.com> <20110311170313.GA10202@kroah.com> <4D7A72E3.1050407@gmail.com> <20110311193433.GB14204@kroah.com> <4D7A8419.6080107@gmail.com> <20110311203032.GA14384@kroah.com> <4D7C9668.3000902@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D7C9668.3000902@gmail.com> 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 Sun, Mar 13, 2011 at 12:03:20PM +0200, Nikolai Kondrashov wrote: > Sometime ago I've found this hack on some forum, which I use currently > to set the brightness: > > setpci -s 00:02.0 f4.b="$HEX_BYTE" > > It allows finer control of the brightness, but it seems it operates directly > on the video card PCI register. I assume there is no sane way to use > this interface from the platform driver, right? Yes, do not do this, it causes all sorts of problems in the end, not the least being the BIOS doesn't know what is going on at all as you are changing the brightness without it knowing it. thanks, greg k-h