Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751897AbdIQSW4 (ORCPT ); Sun, 17 Sep 2017 14:22:56 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:40266 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751479AbdIQSWy (ORCPT ); Sun, 17 Sep 2017 14:22:54 -0400 Date: Sun, 17 Sep 2017 20:22:51 +0200 From: Pavel Machek To: Jacek Anaszewski Cc: Dmitry Torokhov , "linux-input@vger.kernel.org" , David Lin , Jonathan Corbet , Richard Purdie , Hans de Goede , Greg Kroah-Hartman , Rob Herring , Rom Lemarchand , "linux-doc@vger.kernel.org" , lkml , "linux-leds@vger.kernel.org" Subject: Re: Vibrations in input vs. LED was Re: [PATCH v2 0/3] led: ledtrig-transient: add support for hrtimer Message-ID: <20170917182251.GA15328@amd> References: <20170913175400.42744-1-dtwlin@google.com> <20170913202032.GA30844@amd> <9c75c3a9-4123-c7f3-7725-45ba752d672a@gmail.com> <20170914205804.GA24339@amd> <7a611993-ebaa-08bb-b10c-ebe4fb9ca33a@gmail.com> <0076adca-f843-f99f-09ce-b9839b3e7706@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="5mCyUwZo2JvN/JJP" Content-Disposition: inline In-Reply-To: <0076adca-f843-f99f-09ce-b9839b3e7706@gmail.com> 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: 2295 Lines: 62 --5mCyUwZo2JvN/JJP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > If your objection is that FF is not easily engaged from the shell - > > yes, but I do not think that actual users who want to do vibration do > > that via shell either. On the other hand, can you drop privileges and > > still allow a certain process control your vibrator via LED interface? > > With FF you can pass an FD to whoever you deem worthy and later revoke > > access. > >=20 > > IOW sysfs interfaces are nice for quick hacks, but when you want to > > use them in real frameworks, where you need to think about proper > > namespaces, isolation, etc, etc, other kinds of interfaces might suit > > better. >=20 > I'd leave the decision to the user. We could add a note to the > Documentation/leds/ledtrig-transient.txt that force feedback interface > should be preferable choice for driving vibrate devices. We don't want to leave decision to the user; because then we'll end up with userland applications having to support _both_ interfaces. Plus, it is not really your decision. Dmitry is maintainer of input subsystem, input was doing force feedback for 10+ years, and he already made a decision. > However only if following conditions are met: > - force feedback driver supports gpio driven devices > - there is sample application in tools/input showing how to > setup gpio driven vibrate device with use of ff interface > - it will be possible to setup vibrate interval with 1ms accuracy, > similarly to what the discussed patch allows to do I agree these would be nice. Interested parties are welcome to help there. But I don't think this should have any impact on LED susbystem. Force feedback just does not belong to LED subsystem. Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --5mCyUwZo2JvN/JJP Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlm+vXoACgkQMOfwapXb+vK7WQCdETPjVfk88p9hYTc1h+lJ/Fo/ xZkAn3zDDhhU+g3iFGe7KypE5/9jn00W =DtYN -----END PGP SIGNATURE----- --5mCyUwZo2JvN/JJP--