From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH v5 2/6] leds: triggers: Add a keyboard backlight trigger Date: Fri, 25 Nov 2016 10:56:49 +0100 Message-ID: <20161125095649.GB4062@amd> References: <4fcc36c6-498b-0ce7-a7c8-28c214ccef88@redhat.com> <20161122145825.GS13735@pali> <6e8c3884-fec1-461a-e9b8-2020176ada93@samsung.com> <20161124091525.GG13735@pali> <20161124142647.GJ13735@pali> <50225a88-b928-c61b-bf6f-6c85fb6a9082@samsung.com> <20161124153651.GL13735@pali> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Pd0ReVV5GZGQvF3a" Return-path: Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:53201 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751350AbcKYJ4w (ORCPT ); Fri, 25 Nov 2016 04:56:52 -0500 Content-Disposition: inline In-Reply-To: <20161124153651.GL13735@pali> Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org To: Pali =?iso-8859-1?Q?Roh=E1r?= Cc: Jacek Anaszewski , gdg@zplane.com, Hans de Goede , Jacek Anaszewski , Darren Hart , Matthew Garrett , Henrique de Moraes Holschuh , Richard Purdie , ibm-acpi-devel@lists.sourceforge.net, platform-driver-x86@vger.kernel.org, linux-leds@vger.kernel.org --Pd0ReVV5GZGQvF3a Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu 2016-11-24 16:36:51, Pali Roh=E1r wrote: > On Thursday 24 November 2016 16:32:06 Jacek Anaszewski wrote: > > Since it has been reported that POLLPRI notifications on brightness > > file can lead to increased power consumption, and having my above > > statement I don't think that it is a good idea to use brightness > > file for this. >=20 > How is brightness file different from others that it cannot issue > POLLPRI notification? Reading "brightness" may or may not give you current brightness of the led, depending on hardware limitations -- and you can't know. (It may give you maximum brightness of trigger) Reading "hw_current_brightness" file (if present) will give you current brightness. In addition, it is pollable. Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --Pd0ReVV5GZGQvF3a Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlg4CuEACgkQMOfwapXb+vJJjwCbBLjLEfUDomM8heOHckqEc0jN fnwAoKu3t86XD6aEHliTIeLDeYKL4riG =DXO2 -----END PGP SIGNATURE----- --Pd0ReVV5GZGQvF3a--