From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751153AbcGNLze (ORCPT ); Thu, 14 Jul 2016 07:55:34 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:28168 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054AbcGNLzb (ORCPT ); Thu, 14 Jul 2016 07:55:31 -0400 X-AuditID: cbfec7f4-f796c6d000001486-30-57877daf4767 Message-id: <57877DAE.8080401@samsung.com> Date: Thu, 14 Jul 2016 13:55:26 +0200 From: Jacek Anaszewski User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130804 Thunderbird/17.0.8 MIME-version: 1.0 To: Thomas Gleixner Cc: Peter Zijlstra , Ingo Molnar , Anna-Maria Gleixner , LKML , rt@linutronix.de, Richard Cochran , Sebastian Andrzej Siewior , Linus Torvalds , Linus Walleij , Paul Gortmaker , Richard Purdie , linux-leds@vger.kernel.org Subject: Re: [patch V2 43/67] leds/trigger/cpu: Convert to hotplug state machine References: <20160713153219.128052238@linutronix.de> <20160713153336.465496902@linutronix.de> <57873CFF.1010803@samsung.com> <20160714074713.GA17287@gmail.com> <5787490F.5000105@samsung.com> <20160714094154.GY30154@twins.programming.kicks-ass.net> <57877640.4020004@samsung.com> In-reply-to: Content-type: text/plain; charset=ISO-8859-1; format=flowed Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFupgkeLIzCtJLcpLzFFi42I5/e/4Vd0Nte3hBieNLd5dWM5mMe3iJGaL KX+WM1lc3jWHzWLrm3WMFqv/nWK0uLb3OLPF8d4DTBa9XTuZLHbvespqcfXOQUaLzZumMls8 6nvL7sDrsXmFlsemVZ1sHneu7WHzeHfuHLvHiRm/WTz2zP/B6vF5k5zH+i1bmQI4orhsUlJz MstSi/TtErgydnQ0sxcs4a44vrCfrYHxNUcXIyeHhICJxM5fjSwQtpjEhXvr2boYuTiEBJYy SjycMI0ZwnnGKHG34x0zSBWvgJbE83XPGEFsFgFVifsHJrGD2GwChhI/X7xmArFFBSIk/pze xwpRLyjxY/I9sA0iAhoSGy/dApvDLPCMWaLtqBGILSwQIDHt1gcWiGWnmCSWrVkCVsQpYCGx +80uJogGa4mVk7YxQtjyEpvXvGWewCgwC8mOWUjKZiEpW8DIvIpRNLU0uaA4KT3XUK84Mbe4 NC9dLzk/dxMjJH6+7GBcfMzqEKMAB6MSD++DvLZwIdbEsuLK3EOMEhzMSiK896rbw4V4UxIr q1KL8uOLSnNSiw8xSnOwKInzzt31PkRIID2xJDU7NbUgtQgmy8TBKdXAWMP5dMvJY/oR2Xst JWyDZ6Z3bttuuSR+61X2pK2XLgr8+8LyfdUU/ucr7WY1bp1qIbzsy3W2Lcah7zLKtjFrr/61 KjMiNb5NEeh8lpaZmTcX6MwWdP1hv82Jq8d1df4qnoLVdged2vYtz+aoiMtIMlEMUVqmbK12 +GnLv7/tbbpHIi26lD8psRRnJBpqMRcVJwIAm25zVJsCAAA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/14/2016 01:33 PM, Thomas Gleixner wrote: > On Thu, 14 Jul 2016, Jacek Anaszewski wrote: >> On 07/14/2016 11:41 AM, Peter Zijlstra wrote: >>> On Thu, Jul 14, 2016 at 10:10:55AM +0200, Jacek Anaszewski wrote: >>>> On 07/14/2016 09:47 AM, Ingo Molnar wrote: >>>>> >>>>> * Jacek Anaszewski wrote: >>>>> >>>>>>> @@ -133,7 +125,13 @@ static int __init ledtrig_cpu_init(void) >>>>>>> } >>>>>>> >>>>>>> register_syscore_ops(&ledtrig_cpu_syscore_ops); >>>>>>> - register_cpu_notifier(&ledtrig_cpu_nb); >>>>>>> + >>>>>>> + /* >>>>>>> + * FIXME: Why needs this to happen in the interrupt disabled >>>>>>> + * low level bringup phase of a cpu? >>>>>>> + */ >>> >>>> Thanks for the explanation. I'm OK with that approach. >>> >>> Since we have your attention, could you perhaps attempt to answer the >>> question so we can fix the fixme? >>> >> >> This is the way how all led triggers are being registered. >> >> Once a trigger module is loaded it needs to be registered in >> the LED Trigger core. > > That does not explain WHY this needs to happen in the low level bringup phase > of the CPU with interrupts disabled and can't be done from the normal ONLINE > callbacks in thread context. It was before my time in kernel, so I can only suppose that it was the easiest way. Does it introduce some problems? -- Best regards, Jacek Anaszewski