From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Sender: rtc-linux@googlegroups.com Received: from NAM03-CO1-obe.outbound.protection.outlook.com (mail-co1nam03on0066.outbound.protection.outlook.com. [104.47.40.66]) by gmr-mx.google.com with ESMTPS id z64si859886pfi.8.2017.08.21.06.00.52 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 21 Aug 2017 06:00:52 -0700 (PDT) Subject: Re: [rtc-linux] RTC used as a module To: Alexandre Belloni , Michal Simek CC: Michal Simek , John Stultz , "rtc-linux@googlegroups.com" References: <8f181912-d6b1-fe2b-92ef-df2cb26f3f02@xilinx.com> <59e7661e-7e1f-a11e-93c2-9a4bbe9ebe1a@xilinx.com> <20170820220329.uzx3ryehq75qruwz@piout.net> <44ce48f1-73bb-1b88-1e92-327e80f09f96@monstr.eu> <20170821121344.emzboqji3hhakzpf@piout.net> <20170821124720.cmudjhugpssjuag6@piout.net> <20170821125344.ch36irhbmuyda7vw@piout.net> From: Michal Simek Message-ID: <44ceadeb-812a-e639-4c53-4cc11eb9dec4@xilinx.com> Date: Mon, 21 Aug 2017 15:00:24 +0200 MIME-Version: 1.0 In-Reply-To: <20170821125344.ch36irhbmuyda7vw@piout.net> Content-Type: text/plain; charset="UTF-8" Reply-To: rtc-linux@googlegroups.com List-ID: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , On 21.8.2017 14:53, Alexandre Belloni wrote: > On 21/08/2017 at 14:47:20 +0200, Alexandre Belloni wrote: >> On 21/08/2017 at 14:19:07 +0200, Michal Simek wrote: >>> On 21.8.2017 14:13, Alexandre Belloni wrote: >>>> On 21/08/2017 at 12:50:34 +0200, Michal Simek wrote: >>>>> Hi, >>>>> >>>>> On 21.8.2017 00:03, Alexandre Belloni wrote: >>>>>> Hi Michal, >>>>>> >>>>>> I've just send a patch to fix this issue (and avoid your other patch). >>>>>> >>>>>> Could you test it? (I did test on an atmel platform) >>>>>> >>>>>> Sorry it took so long! >>>>> >>>>> not a problem but it looks like it is still just temporary solution. I >>>>> would expect that you can't unload module when this alarm is used. It if >>>>> it is not used then you should be able to remove it. >>>>> >>>> >>>> Yes, the alarmtimer handling needs to be made more flexible, especially >>>> in the rtc device selection. >>> >>> ok. What about to extend that commit message for the patch you sent to >>> explicitly say that this is temporary solution and what should be the >>> right fix? >>> >>> Maybe you can also add link that patch which introduced this issue. >>> It was in that patch I sent. >>> >> >> You didn't pinpoint the correct patch. The patch introducing the issue >> you were seeing (i.e. being able to remove the module) is >> 8bc0dafb5cf38a19484dfb16e2c6d29e85820046. Before this patch, >> rtc_class_open() was called and this prevented the module from being >> removed (it does try_module_get). For now, this is how the feature has >> been implemented since 2011 and nobody cared enough to change that >> behaviour. >> > > To be clear, I'm not saying this should not be done. I'm just try to > explain that this would not be a fix but rather a feature improvement. I am not quite sure I agree with this description. It doesn't mean that none care about this from 2011 that this is correct behavior. You know much more than I in this area but it seems to me quite normal that if you have module and features which implement and you are not using them that you can remove module. It means your patch is a temporary solution for bug introduced in 2011 and found in 2016/2017. Thanks, Michal -- You received this message because you are subscribed to "rtc-linux". Membership options at http://groups.google.com/group/rtc-linux . Please read http://groups.google.com/group/rtc-linux/web/checklist before submitting a driver. --- You received this message because you are subscribed to the Google Groups "rtc-linux" group. To unsubscribe from this group and stop receiving emails from it, send an email to rtc-linux+unsubscribe@googlegroups.com. For more options, visit https://groups.google.com/d/optout.