Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030343AbXBZRLp (ORCPT ); Mon, 26 Feb 2007 12:11:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030345AbXBZRLo (ORCPT ); Mon, 26 Feb 2007 12:11:44 -0500 Received: from py-out-1112.google.com ([64.233.166.183]:62581 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030343AbXBZRLn (ORCPT ); Mon, 26 Feb 2007 12:11:43 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:subject:from:to:cc:in-reply-to:references:content-type:date:message-id:mime-version:x-mailer:content-transfer-encoding; b=UeQMkz10ij/4BqEOFqkaVM5dxQ18z4f3FqRGTLuERhZBwmiFpRvMc8pT4pA62sAiSJ7rIEHGPKAoQwC4+LhYIZebD0NbQ4ko+Ot4VjB7EZH/oLQnyZjRHgFZ3PbB1NpFefs735jcPuBCWgY9I/47GiDndM5TVXHFXQZCaN2GKjE= Subject: Re: [Linux-fbdev-devel] 2.6.21-rc1 dims my LCD From: "Antonino A. Daplas" To: linux-fbdev-devel@lists.sourceforge.net Cc: Jiri Kosina , linux-kernel@vger.kernel.org, Henrique de Moraes Holschuh , Richard Purdie In-Reply-To: <1172504617.5824.102.camel@localhost.localdomain> References: <1172490091.5824.30.camel@localhost.localdomain> <20070226142157.GA2909@khazad-dum.debian.net> <1172501357.5824.91.camel@localhost.localdomain> <1172504617.5824.102.camel@localhost.localdomain> Content-Type: text/plain Date: Tue, 27 Feb 2007 01:13:59 +0800 Message-Id: <1172510039.7101.3.camel@daplas> Mime-Version: 1.0 X-Mailer: Evolution 2.8.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1904 Lines: 43 On Mon, 2007-02-26 at 15:43 +0000, Richard Purdie wrote: > On Mon, 2007-02-26 at 16:24 +0100, Jiri Kosina wrote: > > On Mon, 26 Feb 2007, Richard Purdie wrote: > > > > > Jiri: I've appended a patch that should already be queued, could you > > > test and see if it solves the problem. > > > > Thanks. In the meantime I have gone through the code and I can confirm > > that this is the root cause of what I am observing. > > > > Now regarding the patch - at the time when the dim happened previously, > > currently there is a observable blink (after which the brightness is > > correct). > > The reason for the behaviour is that its turning the backlight down/off > to save power as it thinks the screen is blank. The blink therefore > makes sense as far as the backlight class is concerned and its working > as intended now. > > > I have put some debugging printk() into fb_notifier_callback(), > > and it turns out that on FB_EVENT_CONBLANK, there are two successive calls > > to backlight_update_status(), second immediately following the first one: > > > > Feb 26 15:11:14 thunder kernel: calling backlight_update_status() with bd->props.fb_blank == 1, bd->props.brightness == 0 > > Feb 26 15:11:14 thunder kernel: calling backlight_update_status() with bd->props.fb_blank == 0, bd->props.brightness == 0 > > > > Is this really a right thing to do? Well, no, the console should not blank and immediately unblank. Of course, the console can blank after some time and can be induced to unblank after a keyboard event, for example. Besides the debugging printk's, can you also add something like WARN_ON(1); so you can get a tracing too. Tony - 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/