From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lina Iyer Subject: Re: [PATCH v9 2/9] qcom: spm: Add Subsystem Power Manager driver Date: Wed, 26 Nov 2014 08:20:03 -0700 Message-ID: <20141126152003.GC594@linaro.org> References: <1414194024-55547-1-git-send-email-lina.iyer@linaro.org> <1414194024-55547-3-git-send-email-lina.iyer@linaro.org> <54662622.2020307@linaro.org> <20141119174339.GA891@linaro.org> <5475B724.80202@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Return-path: Received: from mail-pa0-f54.google.com ([209.85.220.54]:38594 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753492AbaKZPUG (ORCPT ); Wed, 26 Nov 2014 10:20:06 -0500 Received: by mail-pa0-f54.google.com with SMTP id fb1so3062657pad.13 for ; Wed, 26 Nov 2014 07:20:06 -0800 (PST) Content-Disposition: inline In-Reply-To: <5475B724.80202@linaro.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Daniel Lezcano Cc: khilman@linaro.org, sboyd@codeaurora.org, galak@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, lorenzo.pieralisi@arm.com, msivasub@codeaurora.org, devicetree@vger.kernel.org On Wed, Nov 26 2014 at 04:19 -0700, Daniel Lezcano wrote: >On 11/19/2014 06:43 PM, Lina Iyer wrote: >>On Fri, Nov 14 2014 at 08:56 -0700, Daniel Lezcano wrote: >>>On 10/25/2014 01:40 AM, Lina Iyer wrote: >> > >>>>+ >>>>+ if ((cpu > -1) && !cpuidle_drv_init) { >>>>+ platform_device_register(&qcom_cpuidle_device); >>>>+ cpuidle_drv_init = true; >>>>+ } >>> >>>'cpu' is always > -1. >>> >>OK. I was hoping to use -1 for not a cpu (i.e, L2) SPM. For now, I will >>change. >> >> >>>If the 'spm_get_drv' succeed, cpu is no longer equal to -EINVAL. >>>Otherwise we do not reach this point because we return right after >>>spm_get_drv with an error. >>> >>>Adding the platform_device_register depending in a static variable is >>>not very nice. Why not add it explicitely in a separate init routine >>>we know it will be called one time (eg. at the same place than cpufreq >>>is) ? >>> >>We want to register the cpuidle device only if any of the SPM devices >>have been probed. >> >>Ideally, Stephen and I would like to register cpuidle device separately >>for each CPU SPM, when it is probed, so we would invoke cpuidle driver >>and thereby the low power modes only for those cpus. However, the >>complexity to do that, AFAICS, is very complex. I would need to change >>quite a bit of the framework and in the cpuidle driver, I may have to >>stray from the recommended format. >> >>Here I set up cpuidle device, when I know atleast 1 cpu is ready to >>allow low power modes. > >Yes, instead of using the generic cpuidle_register function, you can >use the low level functions for that. > >One call to cpuidle_register_driver in a single place and then >cpuidle_register_device for each spm probe. > >Wouldn't make sense ? Yes, but there are some assumptions if we dont use MULTIPLE_CPUIDLE_DRIVERS like this - static void __cpuidle_driver_init(struct cpuidle_driver *drv) { int i; drv->refcnt = 0; // Overwrites any cpuidle_driver_get() The clean way was to use MULTIPLE_CPUIDLE_DRIVERS, which seems like an incorrect use for this SoC. Thanks, Lina