From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758281AbcBXQk6 (ORCPT ); Wed, 24 Feb 2016 11:40:58 -0500 Received: from mx-guillaumet.finsecur.com ([91.217.234.131]:53246 "EHLO guillaumet.finsecur.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757947AbcBXQkz (ORCPT ); Wed, 24 Feb 2016 11:40:55 -0500 X-Greylist: delayed 1204 seconds by postgrey-1.27 at vger.kernel.org; Wed, 24 Feb 2016 11:40:55 EST Date: Wed, 24 Feb 2016 17:20:46 +0100 From: Sylvain Rochet To: Romain Izard Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Boris Brezillon , Daniel Lezcano , Nicolas Ferre , Alexandre Belloni , Thomas Gleixner Message-ID: <20160224162046.GA28743@finsecur.com> References: <1456329882-20709-1-git-send-email-romain.izard.pro@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1456329882-20709-1-git-send-email-romain.izard.pro@gmail.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-SA-Exim-Connect-IP: 172.16.8.13 X-SA-Exim-Mail-From: sylvain.rochet@finsecur.com Subject: Re: [PATCH v2] clocksource: atmel-pit: register as a sched_clock X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on guillaumet.finsecur.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Wed, Feb 24, 2016 at 05:04:42PM +0100, Romain Izard wrote: > Register the counter of the Periodic Interval Timer as a possible source > for sched_clock. Keep the timer running even if the related clockevent > is disabled. > > This provides a better precision than the jiffies-based default. The > TCB clocksource does not work, as it is registered too late in the > initialization sequence. I have mixed feelings about that, but this is probably just a misunderstanding from my part. The PIT timer should not be used for systems with PM_SUSPEND enabled and used because it takes ages to synchronize on resume, how does this patch affect that ? Ref: commit ac34ad27fc ("clockevents: Do not suspend/resume if unused") Sylvain