Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751375AbaLPLqh (ORCPT ); Tue, 16 Dec 2014 06:46:37 -0500 Received: from mail-wg0-f47.google.com ([74.125.82.47]:59761 "EHLO mail-wg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751215AbaLPLqf (ORCPT ); Tue, 16 Dec 2014 06:46:35 -0500 MIME-Version: 1.0 In-Reply-To: <1418731028.WfBPmyK53y@avalon> References: <20141216094854.22639.69181.sendpatchset@w520> <54901420.50403@linaro.org> <1418731028.WfBPmyK53y@avalon> Date: Tue, 16 Dec 2014 20:46:33 +0900 Message-ID: Subject: Re: [PATCH] clocksource: sh_tmu: Set cpu_possible_mask to fix SMP broadcast From: Magnus Damm To: Laurent Pinchart Cc: Daniel Lezcano , linux-kernel , SH-Linux , "Simon Horman [Horms]" , Geert Uytterhoeven , Thomas Gleixner Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Laurent, On Tue, Dec 16, 2014 at 8:20 PM, Laurent Pinchart wrote: > Hi Daniel, > > On Tuesday 16 December 2014 12:14:40 Daniel Lezcano wrote: >> On 12/16/2014 10:48 AM, Magnus Damm wrote: >> > From: Magnus Damm >> > >> > Update the TMU driver to use cpu_possible_mask as cpumask to make >> > r8a7779 SMP work as expected with or without the ARM TWD timer. >> > >> > Signed-off-by: Magnus Damm >> >> Applied as a 3.18 fix. > > You're a bit too fast, I haven't had time to review the patch yet. > >> ps: May I suggest to use the CLOCK_EVT_FEAT_DYNIRQ flag for this driver ? >> >> > --- >> > >> > drivers/clocksource/sh_tmu.c | 2 +- >> > 1 file changed, 1 insertion(+), 1 deletion(-) >> > >> > --- 0001/drivers/clocksource/sh_tmu.c >> > +++ work/drivers/clocksource/sh_tmu.c 2014-12-16 17:49:49.000000000 +0900 >> > @@ -428,7 +428,7 @@ static void sh_tmu_register_clockevent(s >> > >> > ced->features = CLOCK_EVT_FEAT_PERIODIC; >> > ced->features |= CLOCK_EVT_FEAT_ONESHOT; >> > ced->rating = 200; >> > - ced->cpumask = cpumask_of(0); >> > + ced->cpumask = cpu_possible_mask; > > Magnus, how thoroughly have you tested this ? The TMU is indeed usable by all > CPUs, so setting the CPU mask to cpu_possible_mask makes sense, but last time > I've tried that it broke the broadcast timer due to the heuristics used by the > clock events core code. Uhm, so I've tested this particular patch on r8a7779 but I do agree that the TMU is used on a bunch of SoCs if that's what you mean. I don't see how it is different from any other of our timers though, and those got fixed like this earlier. I wonder if you may recall an earlier issue with incorrect clock event priorities and code somehow working-by-accident without the mask set as expected? > Could you please confirm that you've tested both CONFIG_PREEMPT_NONE and > CONFIG_PREEMPT with and without the ARM TWD times, and that you've booted to > userspace and tested timer broadcast on all CPUs ? No I have not. I've booted to user space in initramfs with DT-based TWD on Multiplatform for r8a7779. Without this fix (and other r8a7779 TWD bits) I see a lot of breakage. For instance, TWD and SMP boot is broken on r8a7779 - both legacy and non-legacy. I have not gotten to sh73a0 yet, but I assume it is busted too. Can you please explain to me how the TMU is any different compared to the CMT, MTU2 or STI? =) And no, I don't have any r8a7740 board anymore. Can anyone else test? Cheers, / 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/