From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753493AbbAOLwO (ORCPT ); Thu, 15 Jan 2015 06:52:14 -0500 Received: from down.free-electrons.com ([37.187.137.238]:52704 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752184AbbAOLwM (ORCPT ); Thu, 15 Jan 2015 06:52:12 -0500 Date: Thu, 15 Jan 2015 12:52:09 +0100 From: Alexandre Belloni To: Daniel Lezcano Cc: Nicolas Ferre , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Boris BREZILLON , Maxime Ripard , sylvain.rochet@finsecur.com Subject: Re: [PATCH] clocksource: timer-atmel-pit: don't suspend/resume if unused Message-ID: <20150115115209.GS3843@piout.net> References: <1418911523-28492-1-git-send-email-nicolas.ferre@atmel.com> <54B3D450.7050405@atmel.com> <54B3D88C.80702@linaro.org> <54B7A767.9000205@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <54B7A767.9000205@linaro.org> 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 Hi, I'll do it but only if you review my other series :) On 15/01/2015 at 12:41:27 +0100, Daniel Lezcano wrote : > On 01/13/2015 11:47 AM, Thomas Gleixner wrote: > >On Mon, 12 Jan 2015, Daniel Lezcano wrote: > > > >>On 01/12/2015 03:04 PM, Nicolas Ferre wrote: > >>>Le 18/12/2014 15:05, Nicolas Ferre a écrit : > >>>>From: Sylvain Rochet > >>>> > >>>>Waiting for PIT to stop counting takes a long time: > >>>> 1/(Master clock/prescaler/PIVR) > >>>>= 1/(133 MHz /16 /2^20) > >>>>= 126 ms > >>>> > >>>>Up to 126 ms if master clock is set to 133 MHz, skipping suspend/resume > >>>>of the unused PIT device reduce (suspend time + resume time) from ~140 ms > >>>>to ~17 ms. > >>>> > >>>>Signed-off-by: Sylvain Rochet > >>>>[nicolas.ferre@atmel.com: move to newer clocksource driver] > >>>>Signed-off-by: Nicolas Ferre > >>>>Cc: Daniel Lezcano > >>>>--- > >>>>Hi Sylvain, > >>>> > >>>>I re-worked (and "Acked") your patch so it can be applied on the newer > >>>>Mainline > >>>>kernels. Beware, I changed the "subject line" as well. The PIT driver > >>>>moved > >>>>recently (3.18). > >>>> > >>>>Daniel, > >>>>Can you take this patch in your tree? > >>> > >>>Hi Daniel, > >>> > >>>Anything prevents this patch from being merged (aka ping ;-))? > >> > >>[Cc'ed tglx]. > >> > >>Hi Nico, > >> > >>thanks for the head up. > >> > >>Nothing prevents it but I am wondering if this change shouldn't be in the > >>generic framework (kernel/time/clocksource.c and kernel/time/clockevents.c), > >>so all drivers will benefit this change ? > > > >Indeed. There is no point in calling suspend/resume for unused > >clockevents. They should be stopped and disabled already. > > Hi Nico, > > are you planning to do the change in the generic framework ? > > Thanks > -- Daniel > > >Now with clocksources this might be different. We have no explicit > >state for this, but its trivial to add one at least for those > >clocksources which have enable/disable callbacks. For the other ones > >not so much. > > > > > > -- > Linaro.org │ Open source software for ARM SoCs > > Follow Linaro: Facebook | > Twitter | > Blog > -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com