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 B44FAC4361B for ; Thu, 10 Dec 2020 13:05:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C87423D99 for ; Thu, 10 Dec 2020 13:05:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388692AbgLJNFC (ORCPT ); Thu, 10 Dec 2020 08:05:02 -0500 Received: from fllv0016.ext.ti.com ([198.47.19.142]:49132 "EHLO fllv0016.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731240AbgLJNE4 (ORCPT ); Thu, 10 Dec 2020 08:04:56 -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 0BAD3uin051755; Thu, 10 Dec 2020 07:03:56 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1607605436; bh=f6EbvCETCqSbP/orqL1NF04MBD/Ro0HKcfNe82m54FY=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=QbYV18BV+ETMCAtJEOvPsyGwtNILsBN0ohNrp9nvzItvWXUpn8qsdQuMqtn6WkRQ9 ojIJE6BqaJ+I2TPH4CVjsVFTiptSk4qutH2wLmpr4WqYttJA5gctrYzgbznrN9lUhW JlWUE9uaLYxpPXBDpiXaJF1lCZ6UFWIQux38b0Tg= Received: from DFLE110.ent.ti.com (dfle110.ent.ti.com [10.64.6.31]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 0BAD3ufN087548 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 10 Dec 2020 07:03:56 -0600 Received: from DFLE110.ent.ti.com (10.64.6.31) by DFLE110.ent.ti.com (10.64.6.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Thu, 10 Dec 2020 07:03:56 -0600 Received: from lelv0327.itg.ti.com (10.180.67.183) by DFLE110.ent.ti.com (10.64.6.31) 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; Thu, 10 Dec 2020 07:03:56 -0600 Received: from [10.250.100.73] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 0BAD3qMV006134; Thu, 10 Dec 2020 07:03:53 -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> From: Grygorii Strashko Message-ID: Date: Thu, 10 Dec 2020 15:03:52 +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: <1607565387.25719.43.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 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? Is "some device" in Kernel mainline? > 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