Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965104AbWBGOyg (ORCPT ); Tue, 7 Feb 2006 09:54:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965105AbWBGOyg (ORCPT ); Tue, 7 Feb 2006 09:54:36 -0500 Received: from tim.rpsys.net ([194.106.48.114]:16582 "EHLO tim.rpsys.net") by vger.kernel.org with ESMTP id S965104AbWBGOyf (ORCPT ); Tue, 7 Feb 2006 09:54:35 -0500 Subject: Re: [PATCH] [RESEND] Add Dell laptop backlight brightness display From: Richard Purdie To: Matthew Garrett Cc: Dmitry Torokhov , linux-kernel@vger.kernel.org In-Reply-To: <20060207135502.GA2770@srcf.ucam.org> References: <20060206191506.GA17395@srcf.ucam.org> <20060206191916.GB17460@srcf.ucam.org> <20060207003748.GA22510@srcf.ucam.org> <200602062237.55653.dtor_core@ameritech.net> <20060207123204.GA1423@srcf.ucam.org> <1139317605.6422.26.camel@localhost.localdomain> <20060207132334.GA2331@srcf.ucam.org> <1139319426.6422.42.camel@localhost.localdomain> <20060207135502.GA2770@srcf.ucam.org> Content-Type: text/plain Date: Tue, 07 Feb 2006 14:54:14 +0000 Message-Id: <1139324054.6422.58.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.4.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1471 Lines: 31 On Tue, 2006-02-07 at 13:55 +0000, Matthew Garrett wrote: > On Tue, Feb 07, 2006 at 01:37:06PM +0000, Richard Purdie wrote: > > On Tue, 2006-02-07 at 13:23 +0000, Matthew Garrett wrote: > > > Would you be open to adding generic support for displaying separate AC > > > and DC brightnesses? Making it driver specific leaves the potential for > > > inconsistencies. > > > > The problem is that AC or DC is not a generic property of backlights but > > specific to your problematic hardware case. You're going to have a to > > find a way to tell if its running on AC or not to report the right value > > in the manner the class requires. > > Realistically, it's impossible > without making the driver depend on ACPI and exporting acpi_ac_get_state > from the ACPI layer, which would be a shame since the rest of the > functionality isn't ACPI dependent at all. If that's what's needed to give the correct behaviour, so be it. In an ideal world, we'd not need the dependency but it sounds unavoidable. You can actually have a soft dependency where it could use the DC value unless ACPI is present in which case it would be more intelligent. The corgi_bl driver does this for the backlight limiting on low power. Richard - 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/