From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752093AbbE0IrY (ORCPT ); Wed, 27 May 2015 04:47:24 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:40424 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751483AbbE0IrU (ORCPT ); Wed, 27 May 2015 04:47:20 -0400 Date: Wed, 27 May 2015 10:47:18 +0200 From: Pavel Machek To: Peter Zijlstra Cc: mingo@redhat.com, linux-kernel@vger.kernel.org, cooloney@gmail.com, rpurdie@rpsys.net, j.anaszewski@samsung.com, linux-leds@vger.kernel.org Subject: Re: CPU LED trigger: add hooks to generic code so that it works on x86 Message-ID: <20150527084718.GA4991@amd> References: <20150527065712.GA4415@amd> <20150527074343.GI19282@twins.programming.kicks-ass.net> <20150527074757.GB1254@amd> <20150527080831.GJ19282@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150527080831.GJ19282@twins.programming.kicks-ass.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 2015-05-27 10:08:31, Peter Zijlstra wrote: > On Wed, May 27, 2015 at 09:47:57AM +0200, Pavel Machek wrote: > > On Wed 2015-05-27 09:43:43, Peter Zijlstra wrote: > > > On Wed, May 27, 2015 at 08:57:12AM +0200, Pavel Machek wrote: > > > > > > > > CPU LED trigger hooks are currently hidden in arm-specific code, which > > > > means that this trigger only works on arm. Add it to the generic > > > > code, so that it works on x86, too. > > > > > > And why do we want to go and slow down the idle loop for everyone? > > > > If the trigger is not configured, this is not slowing down anyone. > > > > If the trigger is configured, well, then the user requested the > > functionality. So we are not slowing down _everyone_, just the people > > that want the blinking. > > What kind of x86 hardware will support this? If its _everything_ distros > will have to enable this and it suddenly becomes a lot of people. It needs directly connected leds. It is useful on thinkpad t40p, for example. Distros should not enable this, IMO. But I don't think overhead is that big in either case. But I wanted to enable it, and result was trigger that can be configured, enabled, and just plain does not work (which is nasty). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html