From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752008AbcLEENK (ORCPT ); Sun, 4 Dec 2016 23:13:10 -0500 Received: from lelnx194.ext.ti.com ([198.47.27.80]:29703 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751758AbcLEENI (ORCPT ); Sun, 4 Dec 2016 23:13:08 -0500 Subject: Re: [PATCH 2/2] ARM: omap: timers: reduce rating of gp_timer clocksource To: Tony Lindgren , Grygorii Strashko References: <1479968355-18860-1-git-send-email-j-keerthy@ti.com> <1479968355-18860-2-git-send-email-j-keerthy@ti.com> <20161202164714.GB4705@atomide.com> <14878d85-1b08-5df1-4e67-6f982ba72019@ti.com> <20161202183139.GF4705@atomide.com> CC: , , , , , Dave Gerlach From: Keerthy Message-ID: Date: Mon, 5 Dec 2016 09:42:24 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20161202183139.GF4705@atomide.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 03 December 2016 12:01 AM, Tony Lindgren wrote: > * Grygorii Strashko [161202 10:02]: >> >> >> On 12/02/2016 10:47 AM, Tony Lindgren wrote: >>> * Grygorii Strashko [161129 08:43]: >>>> >>>> >>>> On 11/24/2016 12:19 AM, Keerthy wrote: >>>>> From: Grygorii Strashko >>>>> >>>>> Now ARM Global timer (rating 300) will not be selected as clocksource, >>>>> because it's initialized after OMAP GP Timer (rating 300) and >>>>> Timekeeping core will not allow to replace clocksource with new one if >>>>> both of them have the same rating. >>>>> >>>>> Reduce rating of OMAP GP Timer (300->290) when it's used as >>>>> clocksource device - this will allow to select ARM Global timer (300) >>>>> as clocksource when enabled. >>>>> >>>>> Signed-off-by: Grygorii Strashko >>>>> Signed-off-by: Dave Gerlach >>>>> Signed-off-by: Keerthy >>>> >>>> Unfortunately, this patch has dependency [1] and can't be used alone as >>>> it will cause ARM Global timer to be selected as clocksource >>>> always on am437x and this will kill cpuidle, because ARM Global timer >>>> is not in always_on domain. >>>> >>>> The intention of enabling ARM Global timer is only for non-pm aware use >>>> cases for RT-kernel latency improvement - where deep cpuidle states are not >>>> enabled. >>> >>> Yeah we need to fix up things to be able to change the clocksource >>> in addition to clockevent. However, currently only cpuidle_coupled >>> knows when the whole system is idle, so quite a bit of work is >>> needed to do that in a sane way. >> >> Also sched_clock and timer_delay ;) > > Yeah sched_clock would need something to save and restore it.. > Not nice :) > >>> What about the first patch in this series? >>> >> >> Fist one is ok. It was originally posted long time ago. > > OK so can you please resend that one more time with proper > Fixes tag on it? Tony, I have posted a v2 with the proper Fixes tag. - Keerthy > > Regards, > > Tony >