Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755526Ab3FQCrP (ORCPT ); Sun, 16 Jun 2013 22:47:15 -0400 Received: from mail-lb0-f178.google.com ([209.85.217.178]:39168 "EHLO mail-lb0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755103Ab3FQCrN (ORCPT ); Sun, 16 Jun 2013 22:47:13 -0400 MIME-Version: 1.0 In-Reply-To: <20130617021342.GJ15043@verge.net.au> References: <20130617002056.7646.54131.sendpatchset@w520> <20130617021342.GJ15043@verge.net.au> Date: Mon, 17 Jun 2013 11:47:11 +0900 Message-ID: Subject: Re: [PATCH/RFC] arm: arch_timer: Do not set C3STOP in case CPU_IDLE=n From: Magnus Damm To: Simon Horman Cc: linux-kernel , Mark Rutland , SH-Linux , Marc Zyngier , Catalin Marinas , John Stultz , Shinya Kuribayashi , Thomas Gleixner Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2012 Lines: 55 Hi Simon, On Mon, Jun 17, 2013 at 11:13 AM, Simon Horman wrote: > On Mon, Jun 17, 2013 at 09:20:56AM +0900, Magnus Damm wrote: >> From: Magnus Damm >> >> Modify the ARM architected timer driver to not set C3STOP >> in case CPU_IDLE is disabled. This is a short term fix that >> allows use of high resolution timers even though no additional >> clock event is registered. >> >> Not-really-Signed-off-by: Magnus Damm >> --- >> >> If someone cares about this case then perhaps it should be >> moved up to the clock event main code. The same issue should >> in theory trigger on all architectures, perhaps x86 people >> hunting for low latency may try to disable CPU_IDLE? >> >> I propose carrying this patch locally to enable high resolution >> timers until CPU_IDLE and an additional clock event is supported. >> >> Observed on r8a73a4 and APE6EVM. > > Hi Magnus, > > Is this patch intended to be picked up by me for the LTSI-3.4.25 based > backports that live in my renesas-backports tree? Yes, correct. The patch was mainly written to satisfy a feature request for your backports, but I noticed that the same issue exists in upstream as well. Ideally I'd like to use the same code for the backport and upstream, but I am not sure if anyone in upstream really cares. The more long term solution is obviously to install a second clock event, perhaps that's good enough. > If so, could you clearly state this (below the '---' is fine) and > include a proper Sob line to indicate that it is fit to be merged > even if that merge is not into mainline. Sure, but I'd like to hear opinions from other people before resending. I will follow your recommendation in next version. Thanks, / magnus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/