From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760251AbcBYJGt (ORCPT ); Thu, 25 Feb 2016 04:06:49 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:43273 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759289AbcBYJGl (ORCPT ); Thu, 25 Feb 2016 04:06:41 -0500 Date: Thu, 25 Feb 2016 10:06:36 +0100 From: Pavel Machek To: Johannes Berg Cc: rpurdie@rpsys.net, j.anaszewski@samsung.com, linux-leds@vger.kernel.org, =?iso-8859-1?Q?Jo=E3o?= Paulo Rechi Vita , "David S. Miller" , Darren Hart , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux@endlessm.com, =?iso-8859-1?Q?Jo=E3o?= Paulo Rechi Vita Subject: Re: custom ioctl-based interface to control LED in networking (was Re: [PATCHv2 09/10] rfkill: Userspace control for airplane mode) Message-ID: <20160225090636.GA32652@amd> References: <1456159001-20307-1-git-send-email-jprvita@endlessm.com> <1456159001-20307-10-git-send-email-jprvita@endlessm.com> <20160223204525.GC16961@amd> <1456260914.9910.34.camel@sipsolutions.net> <20160223214501.GA22501@amd> <1456304509.2050.15.camel@sipsolutions.net> <20160224104611.GB31302@amd> <1456311697.2050.23.camel@sipsolutions.net> <20160224121420.GA5627@amd> <1456320693.2050.30.camel@sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1456320693.2050.30.camel@sipsolutions.net> 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 On Wed 2016-02-24 14:31:33, Johannes Berg wrote: > On Wed, 2016-02-24 at 13:14 +0100, Pavel Machek wrote: > >  > > Why would it need to? It could look at default triggers for the led > > if it really wanted to. > > And then it needs to change them; if anything goes wrong error recovery > is practically impossible since the trigger information is lost > forever. Well, conventional way to solve this is to simply name the led "acer::airplane"... that way it is persistent. We already do that for display/keyboard backlights. > It's not my position to decide which combinations some system > integrator or userspace developer might find useful. > > Even when we add parameters to a trigger (I don't see a generic way to > do that, but please do enlighten me), you're now ignoring the issue of > the userspace controlled GSM modem... Take a look at the blinking triggers. > > > Really what you have here is a concept of "airplane mode", and that > > > concept is specific to the rfkill subsystem. This happens to affect > > > mostly an LED trigger, today, but as a concept it's something that > > > *should* be managed within the rfkill subsystem. > > > > How is that concept used outside the LEDs? What semantics does > > "airplane mode" have? You tried to explain "airplane mode" is not > > well defined up in this thread... > > I'd say it's well-defined for any given set of system software, so if > e.g. NetworkManager decides to define it one way, and connman another > way, there's a definition but the kernel need not interfere with it. So... the LED changes meaning during boot? That's surely not a nice solution. So... you rather store bit in a kernel with unclear semantics, explaining "oh I need to leave the flexibility to userland"? Sorry, that's just ugly. > > I'm not saying that. I'm saying that LED maintainers should be Cced, > > to keep the interfaces consistent. > > I pretty much have to read it that way, since the LED API is in no way > impacted by these changes. Here's a new trigger, with some magic inner > working. No impact on the LED API. New LED trigger and new ioctl for LED control... not matching how LEDs are normally controlled. Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html