Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753845AbbEFFzv (ORCPT ); Wed, 6 May 2015 01:55:51 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:56122 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753502AbbEFFzt (ORCPT ); Wed, 6 May 2015 01:55:49 -0400 Date: Tue, 5 May 2015 22:55:46 -0700 From: Darren Hart To: Gabriele Mazzotta Cc: Pali =?iso-8859-1?Q?Roh=E1r?= , Alex Hung , Matthew Garrett , "platform-driver-x86@vger.kernel.org" , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/3] platform: x86: dell-rbtn: Dell Airplane Mode Switch driver Message-ID: <20150506055546.GA7523@vmdeb7> References: <1416755361-17357-1-git-send-email-pali.rohar@gmail.com> <20150430074429.GT24346@pali> <1828808.mVmCDTOvJh@xps13> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1828808.mVmCDTOvJh@xps13> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2199 Lines: 48 On Tue, May 05, 2015 at 11:23:05PM +0200, Gabriele Mazzotta wrote: > On Thursday 30 April 2015 09:44:29 Pali Roh?r wrote: > > On Thursday 30 April 2015 14:06:27 Alex Hung wrote: > > > Method ABRT is to be used by driver to disable BIOS handling of radio > > > button. So the changes in behaviours observed by Gabriele is expected. > > > I have seen other systems behave the same way. > > > > > > > Right, that after that ARBT call operating system get full control over > > radio devices and ACPI/BIOS will not automatically enable/disable them. > > I think this is OK. > > > > But for that we need also support for manually enable/disable radio > > devices and code for this support is missing. Or do DELLABCE/RBTN acpi > > devices somehow support enabling/disabling it via system/kernel request? > > > > > I do also see firmware only sends Notify(RBTN, 0x80) and no hard block > > > whether ABRT(1) is called or not. Thus keycode are the only option on > > > those machines. > > > > > > > Key is ok, but we *must* have ability to hard block it via some > > ACPI/WMI/BIOS/FW/etc... call. Otherwise ARBT(1) is no go as users should > > be able to enable/disable their radio devices (bluetooth for powersave) > > Does it really matter in the end? As I understand it, radio devices are > off either way. As a point of reference for consideration, we recently dropped the Thinkpad hardware mute button because it seriously complicated everything in what appears to be a similar sort of situation. By eliminating the hardware mute and relying purely on software mute, we were able to provide a much more consistently functional driver. Also note that this driver provided a "software_mute" module parameter to allow the user to control this. I believe this provides some relevant precedent for your consideration. I don't want to add parameters casually, but it could be one is warranted here. -- Darren Hart Intel Open Source Technology Center -- 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/