From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754317AbbFEG6h (ORCPT ); Fri, 5 Jun 2015 02:58:37 -0400 Received: from regular2.263xmail.com ([211.157.152.4]:44556 "EHLO regular2.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750831AbbFEG6e (ORCPT ); Fri, 5 Jun 2015 02:58:34 -0400 X-263anti-spam: KSV:0; X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 X-RL-SENDER: wxt@rock-chips.com X-FST-TO: linux-arm-kernel@lists.infradead.org X-SENDER-IP: 191.101.57.89 X-LOGIN-NAME: wxt@rock-chips.com X-UNIQUE-TAG: X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Message-ID: <5571488A.5040609@rock-chips.com> Date: Fri, 05 Jun 2015 14:58:18 +0800 From: Caesar Wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Kever Yang , Heiko Stuebner CC: Russell King , Dmitry Torokhov , dianders@chromium.org, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/3] ARM: rockchip: ensure CPU to enter WIF state References: <1433479677-18086-1-git-send-email-wxt@rock-chips.com> <1433479677-18086-3-git-send-email-wxt@rock-chips.com> <5571427B.1040406@rock-chips.com> In-Reply-To: <5571427B.1040406@rock-chips.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2015年06月05日 14:32, Kever Yang 写道: > Hi Caesar, > > Subject typo WIF/WFI. OK > > On 06/05/2015 12:47 PM, Caesar Wang wrote: >> In idle mode, core1/2/3 of Cortex-A17 should be either power off or in >> WFI/WFE state. >> we can delay 1ms to ensure the CPU enter WFI state. >> >> Signed-off-by: Caesar Wang >> --- >> >> arch/arm/mach-rockchip/platsmp.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/arch/arm/mach-rockchip/platsmp.c >> b/arch/arm/mach-rockchip/platsmp.c >> index 1230d3d..978c357 100644 >> --- a/arch/arm/mach-rockchip/platsmp.c >> +++ b/arch/arm/mach-rockchip/platsmp.c >> @@ -316,6 +316,9 @@ static void __init >> rockchip_smp_prepare_cpus(unsigned int max_cpus) >> #ifdef CONFIG_HOTPLUG_CPU >> static int rockchip_cpu_kill(unsigned int cpu) >> { >> + /* ensure CPU can enter the WFI/WFE state */ >> + mdelay(1); >> + > Does it matter if core is not in WFI state when we want to power down it? > As HuangTao suggestion, In gerenal, we need enter the WFI state when core power down, right? That will be more better if the hardware can judge the state. Anyway, we can delay 1ms or more to wait the WFI state. That should be more better, right? > Thanks, > - Kever >> pmu_set_power_domain(0 + cpu, false); >> return 1; >> } > > > >