From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacek Anaszewski Subject: Re: [PATCH v5 2/6] leds: triggers: Add a keyboard backlight trigger Date: Thu, 24 Nov 2016 22:35:52 +0100 Message-ID: <5238be1f-d669-07e6-c796-5bc0126cb456@gmail.com> References: <05766b18-026a-2af3-def8-9289ddb55234@samsung.com> <20161124153651.GL13735@pali> <201611241751.27696@pali> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: Received: from mail-wj0-f194.google.com ([209.85.210.194]:35894 "EHLO mail-wj0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966216AbcKXVgk (ORCPT ); Thu, 24 Nov 2016 16:36:40 -0500 In-Reply-To: <201611241751.27696@pali> Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org To: =?UTF-8?Q?Pali_Roh=c3=a1r?= , Jacek Anaszewski Cc: gdg@zplane.com, Hans de Goede , Pavel Machek , 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 On 11/24/2016 05:51 PM, Pali Rohár wrote: > On Thursday 24 November 2016 17:21:19 Jacek Anaszewski wrote: >> On 11/24/2016 04:36 PM, Pali Rohár 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. >>> >>> How is brightness file different from others that it cannot issue >>> POLLPRI notification? >>> >>> I understood that problem is there in case that LED level is >>> changed too many times per second (like by CPU trigger). >>> >>> If this is not that problem can you describe real issue, why we >>> cannot use POLLPRI for brightness file? >> >> It would be inconsistent not to notify all brightness changes on >> brightness file. We should notify all of them or none. > > I understood that we cannot notify about changes done by CPU trigger due > to high power usage... Or not? Exactly. -- Best regards, Jacek Anaszewski