From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel.lezcano@linaro.org (Daniel Lezcano) Date: Wed, 30 Mar 2016 11:31:39 +0200 Subject: [PATCH 1/2] ARM: cpuidle: fix !cpuidle_ops[cpu].init case during init In-Reply-To: <20160330164342.10cf1830@xhacker> References: <1458796269-6158-1-git-send-email-jszhang@marvell.com> <1458796269-6158-2-git-send-email-jszhang@marvell.com> <56F52502.3060308@linaro.org> <20160330151629.0b338365@xhacker> <56FB89A8.90209@linaro.org> <20160330161745.7afd6e48@xhacker> <56FB9125.10507@linaro.org> <20160330164342.10cf1830@xhacker> Message-ID: <56FB9CFB.8050305@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/30/2016 10:43 AM, Jisheng Zhang wrote: > On Wed, 30 Mar 2016 10:41:09 +0200 Daniel Lezcano wrote: > >> On 03/30/2016 10:17 AM, Jisheng Zhang wrote: >>> On Wed, 30 Mar 2016 10:09:12 +0200 Daniel Lezcano wrote: >>> >>>> On 03/30/2016 09:16 AM, Jisheng Zhang wrote: >>>>> Hi Daniel, >>>> >>>> [ ... ] >>>> >>>> Added Lorenzo and Catalin. >>>> >>>>>> Hi Jisheng, >>>>>> >>>>>> this should be handled in the arm_cpuidle_read_ops function. >>>>>> >>>>> >>>>> Thanks for reviewing. After some consideration, I think this patch isn't correct >>>>> There may be platforms which doesn't need the init member at all, although >>>>> currently I don't see such platforms in mainline, So I'll drop this patch >>>>> and send out one v2 only does the optimization. >>>> >>>> There is an inconsistency between ARM and ARM64. The 'cpu_get_ops', the >>>> arm_cpuidle_read_ops from the ARM64 side, returns -EOPNOTSUPP when the >>>> init function is not there for cpuidle. >>> >>> yes. >>> arm64's arm_cpuidle_init() returns -EOPNOTSUPP if init callback isn't defined >>> >>>> >>>> I don't think it is a problem, but as ARM/ARM64 are sharing the same >>>> cpuidle-arm.c driver it would make sense to unify the behavior between >>>> both archs. >>> >>> yes, agree with you. From "unify" point of view, could I move back the suspend >>> callback check and init callback check into arm_cpuidle_init() for arm as V1 does? >> >> Why ? To be consistent with ARM64 ? > > Yes, that's my intention. Well, I don't have a strong opinion on that. ARM64 cpu_ops is slightly different from cpuidle_ops as the cpu boot / hotplug operations are placed in a different place and that explains why on ARM64 we can have an successful 'get_ops' because we use the partially filled structure. On ARM, it is cpuidle_ops only, so we can gracefully fail if the ops are not defined. IMO, it still make sense to keep the checks in arm_cpuidle_read_ops for ARM. -- Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751831AbcC3Jbo (ORCPT ); Wed, 30 Mar 2016 05:31:44 -0400 Received: from mail-wm0-f49.google.com ([74.125.82.49]:35010 "EHLO mail-wm0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750959AbcC3Jbm (ORCPT ); Wed, 30 Mar 2016 05:31:42 -0400 Subject: Re: [PATCH 1/2] ARM: cpuidle: fix !cpuidle_ops[cpu].init case during init To: Jisheng Zhang References: <1458796269-6158-1-git-send-email-jszhang@marvell.com> <1458796269-6158-2-git-send-email-jszhang@marvell.com> <56F52502.3060308@linaro.org> <20160330151629.0b338365@xhacker> <56FB89A8.90209@linaro.org> <20160330161745.7afd6e48@xhacker> <56FB9125.10507@linaro.org> <20160330164342.10cf1830@xhacker> Cc: Lorenzo Pieralisi , Catalin Marinas , linux@arm.linux.org.uk, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org From: Daniel Lezcano Message-ID: <56FB9CFB.8050305@linaro.org> Date: Wed, 30 Mar 2016 11:31:39 +0200 User-Agent: Mozilla/5.0 (X11; Linux i686; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <20160330164342.10cf1830@xhacker> 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 On 03/30/2016 10:43 AM, Jisheng Zhang wrote: > On Wed, 30 Mar 2016 10:41:09 +0200 Daniel Lezcano wrote: > >> On 03/30/2016 10:17 AM, Jisheng Zhang wrote: >>> On Wed, 30 Mar 2016 10:09:12 +0200 Daniel Lezcano wrote: >>> >>>> On 03/30/2016 09:16 AM, Jisheng Zhang wrote: >>>>> Hi Daniel, >>>> >>>> [ ... ] >>>> >>>> Added Lorenzo and Catalin. >>>> >>>>>> Hi Jisheng, >>>>>> >>>>>> this should be handled in the arm_cpuidle_read_ops function. >>>>>> >>>>> >>>>> Thanks for reviewing. After some consideration, I think this patch isn't correct >>>>> There may be platforms which doesn't need the init member at all, although >>>>> currently I don't see such platforms in mainline, So I'll drop this patch >>>>> and send out one v2 only does the optimization. >>>> >>>> There is an inconsistency between ARM and ARM64. The 'cpu_get_ops', the >>>> arm_cpuidle_read_ops from the ARM64 side, returns -EOPNOTSUPP when the >>>> init function is not there for cpuidle. >>> >>> yes. >>> arm64's arm_cpuidle_init() returns -EOPNOTSUPP if init callback isn't defined >>> >>>> >>>> I don't think it is a problem, but as ARM/ARM64 are sharing the same >>>> cpuidle-arm.c driver it would make sense to unify the behavior between >>>> both archs. >>> >>> yes, agree with you. From "unify" point of view, could I move back the suspend >>> callback check and init callback check into arm_cpuidle_init() for arm as V1 does? >> >> Why ? To be consistent with ARM64 ? > > Yes, that's my intention. Well, I don't have a strong opinion on that. ARM64 cpu_ops is slightly different from cpuidle_ops as the cpu boot / hotplug operations are placed in a different place and that explains why on ARM64 we can have an successful 'get_ops' because we use the partially filled structure. On ARM, it is cpuidle_ops only, so we can gracefully fail if the ops are not defined. IMO, it still make sense to keep the checks in arm_cpuidle_read_ops for ARM. -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog