From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Purdie Subject: Re: 2.6.21-rc2 radeon backlight Date: Sat, 03 Mar 2007 16:35:13 +0000 Message-ID: <1172939714.5942.9.camel@localhost.localdomain> References: <87ps7uutsk.fsf@sycorax.lbl.gov> <20070301184531.b3aeafe3.akpm@linux-foundation.org> <87tzx35zkc.fsf@sycorax.lbl.gov> <20070302122920.a2967ebf.akpm@linux-foundation.org> <1172878338.11149.198.camel@localhost.localdomain> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1HNXDa-0005Fp-Do for linux-fbdev-devel@lists.sourceforge.net; Sat, 03 Mar 2007 08:36:22 -0800 Received: from tim.rpsys.net ([194.106.48.114] ident=0) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1HNXDX-0003Zf-Qi for linux-fbdev-devel@lists.sourceforge.net; Sat, 03 Mar 2007 08:36:22 -0800 In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-fbdev-devel-bounces@lists.sourceforge.net Errors-To: linux-fbdev-devel-bounces@lists.sourceforge.net To: James Simmons Cc: linux-fbdev-devel@lists.sourceforge.net, "Antonino A. Daplas" , Alex Romosan , linux-kernel@vger.kernel.org, Yaroslav Halchenko , Henrique de Moraes Holschuh , Andrew Morton , "David S. Miller" On Sat, 2007-03-03 at 16:06 +0000, James Simmons wrote: > > > Richard, is this actually a bug, or is it a config error or something like that? > > > > > > And should we track it as a post-2.6.20 regression? > > > > Its a regression IMO. Arguably its a Kconfig error but a nasty one as > > the defaults cause the problems. Different people seem to have different > > interpretations but to me it appears that the patch from James causes > > backlights to fail to turn on for a variety of devices which worked > > before. > > It is NOT a Kconfig error. The problem is that for many fbdev drivers > the backlight code is broken. For some magic reason it only works on > pmacs. Most likely because the firmware properly sets up the backlight. > Plus we have the conflict with acpi backlight. > Think about it. Enabling the backlight code breaks the backlight. > Without the backlight driver the default behaviour of the backlight works. > Who sets up the default behavior? I don't have a LCD panel with a > backlight othewise I would track the problem down. I not arguing several fb driver's backlight code isn't broken, it is. We have a Kconfig problem though since we used to stop users selecting things that didn't work and now we're allowing them. Worse still, the defaults break for people. That is a regression. Anyhow, the patch I proposed should let people enable/disable it at runtime with defaults known to work which should address the problem until someone figures out how to fix the backlight drivers themselves properly. Cheers, Richard ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV