From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59DA0C2BB48 for ; Mon, 14 Dec 2020 20:10:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C8C222510 for ; Mon, 14 Dec 2020 20:10:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502981AbgLNUJu (ORCPT ); Mon, 14 Dec 2020 15:09:50 -0500 Received: from fllv0016.ext.ti.com ([198.47.19.142]:47208 "EHLO fllv0016.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2502860AbgLNUJl (ORCPT ); Mon, 14 Dec 2020 15:09:41 -0500 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 0BEK8L4L073067; Mon, 14 Dec 2020 14:08:21 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1607976501; bh=bYx/KPXoQnydtHvU0A93Ft8RQtsoKRmWYVYqEzohC3E=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=ca6cYdkcTVbnkADiNBN0eInegJ8WDq4+PFGkFWDOfk4/LXyfDKsgmkIHAkRgfcDpP 0CJgnGqdd7ya9oPUwsDPmaq5ZAkF7MsJGCw8s4RmyZq3mfbtPoNr2EMQBOh+D2Rbuq ClrMKStJktpBh5LWXg0cUwUzr56JkyJM4WLnHvfU= Received: from DLEE102.ent.ti.com (dlee102.ent.ti.com [157.170.170.32]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 0BEK8LOM088012 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 14 Dec 2020 14:08:21 -0600 Received: from DLEE102.ent.ti.com (157.170.170.32) by DLEE102.ent.ti.com (157.170.170.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Mon, 14 Dec 2020 14:08:21 -0600 Received: from lelv0326.itg.ti.com (10.180.67.84) by DLEE102.ent.ti.com (157.170.170.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Mon, 14 Dec 2020 14:08:21 -0600 Received: from [10.250.100.73] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 0BEK8Hgr080343; Mon, 14 Dec 2020 14:08:18 -0600 Subject: Re: [v2] i2c: mediatek: Move suspend and resume handling to NOIRQ phase To: Qii Wang CC: Wolfram Sang , , , , , , , References: <1605701861-30800-1-git-send-email-qii.wang@mediatek.com> <20201202153543.GG874@kunai> <1606958735.25719.29.camel@mhfsdcap03> <629d171a-0e77-3d74-ae23-e6439dcf17b7@ti.com> <1607326431.25719.33.camel@mhfsdcap03> <1607565387.25719.43.camel@mhfsdcap03> <1607935685.25719.49.camel@mhfsdcap03> From: Grygorii Strashko Message-ID: <765c182a-5c68-b408-85ca-f757e891090e@ti.com> Date: Mon, 14 Dec 2020 22:08:16 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1607935685.25719.49.camel@mhfsdcap03> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On 14/12/2020 10:48, Qii Wang wrote: > On Thu, 2020-12-10 at 15:03 +0200, Grygorii Strashko wrote: >> >> On 10/12/2020 03:56, Qii Wang wrote: >>> On Mon, 2020-12-07 at 18:35 +0200, Grygorii Strashko wrote: >>>> >>>>> >>>>> On Thu, 2020-12-03 at 10:01 +0200, Grygorii Strashko wrote: >>>>>> >>>>>> On 03/12/2020 03:25, Qii Wang wrote: >>>>>>> On Wed, 2020-12-02 at 16:35 +0100, Wolfram Sang wrote: >>>>>>>> Hi, >>>>>>>> >>>>>>>>> Some i2c device driver indirectly uses I2C driver when it is now >>>>>>>>> being suspended. The i2c devices driver is suspended during the >>>>>>>>> NOIRQ phase and this cannot be changed due to other dependencies. >>>>>>>>> Therefore, we also need to move the suspend handling for the I2C >>>>>>>>> controller driver to the NOIRQ phase as well. >>>>>>>>> >>>>>>>>> Signed-off-by: Qii Wang >>>>>>>> >>>>>>>> Is this a bugfix and should go into 5.10? Or can it wait for 5.11? >>>>>>>> >>>>>>> >>>>>>> Yes, Can you help to apply it into 5.10? Thanks >>>>>> >>>>>> To be honest if you still do have any i2c device which accessing i2c buss after _noirq >>>>>> stage and your driver does not implement .master_xfer_atomic() - you definitely have a bigger problem. >>>>>> So adding IRQF_NO_SUSPEND sound like a hack and probably works just by luck. >>>>>> >>>>> >>>>> At present, it is only a problem caused by missing interrupts, >>>>> and .master_xfer_atomic() just a implement in polling mode. Why not set >>>>> the interrupt to a state that can always be triggered? >>>>> >>>>> >>>> >>>> Because you must not use any IRQ driven operations after _noirq suspend state as it might (and most probably will) >>>> cause unpredictable behavior later in suspend_enter(): >>>> >>>> arch_suspend_disable_irqs(); >>>> BUG_ON(!irqs_disabled()); >>>> ^after this point any IRQ driven I2C transfer will cause IRQ to be re-enabled >>>> >>>> if you need turn off device from platform callbacks - .master_xfer_atomic() has to be implemented and used. >>>> >>> Maybe my comment is a bit disturbing.Our purpose is not to call i2c and >>> use interrupts after _noirq pauses.So We use >>> i2c_mark_adapter_suspended&i2c_mark_adapter_resumed to block these i2c >>> transfers， There will not have any IRQ driven I2C transfer after this >>> point: >>> arch_suspend_disable_irqs(); >>> BUG_ON(!irqs_disabled()); >>> But some device driver will do i2c transfer after >>> dpm_noirq_resume_devices in dpm_resume_noirq(PMSG_RESUME) when our >>> driver irq hasn't resume. >>> void dpm_resume_noirq(pm_message_t state) >>> { >>> dpm_noirq_resume_devices(state); >> >> Just to clarify. You have resume sequence in dpm_noirq_resume_devices >> dpm_noirq_resume_devices -> resume I2C -> resume some device -> do i2c transfer after? >> > > Yes. huh. First consider IRQF_EARLY_RESUME - it's better, but still will be a hack > >> Is "some device" in Kernel mainline? >> > > The problematic device driver is drivers/regulator/da9211-regulator.c in > Kernel mainline. regulator is passive device, somebody should call it !? And da9211-regulator IRQ handler should remain disabled till resume_device_irqs() call. note. regulator_class implements only static const struct dev_pm_ops __maybe_unused regulator_pm_ops = { .suspend = regulator_suspend, .resume = regulator_resume, }; > >>> resume_device_irqs(); >>> device_wakeup_disarm_wake_irqs(); >>> cpuidle_resume(); >>> } >>> .master_xfer_atomic() seems to be invalid for this question at this >>> time? >>> >> > -- Best regards, grygorii