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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BABA2CDB482 for ; Fri, 13 Oct 2023 10:39:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230036AbjJMKjh (ORCPT ); Fri, 13 Oct 2023 06:39:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230429AbjJMKjb (ORCPT ); Fri, 13 Oct 2023 06:39:31 -0400 Received: from EUR04-DB3-obe.outbound.protection.outlook.com (mail-db3eur04on2083.outbound.protection.outlook.com [40.107.6.83]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5F7F10B; Fri, 13 Oct 2023 03:39:15 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=aJIiPxcj/F0L/Vwlpdv1kKpoiyQtki06QGl8GI0MQk4MjOWlITRUvBqlPqwjeBCjNLeM+rxQyooubEMw2H1/t2XJnZB1V+9pbuYZmzS+ZwHHWZYSxUGai17tYZdsiNGPpm65na1aq951L9HP5dcD0UWxGmF6sirlcqPIQQj4fhUWDXSwqr377hAWbEJbPoUk5J1qa3+Z5JSHTwkMLPWFws9zA9gJhTZx1uo25prxLargo33jwiJDhfZMlqc1t2fIK0Of+hMcuYD69Lw7Tpr9aqJgYYTi6dNeOOnppeFvfPqlqAfaKIqCroJrNs+z0t+vDbEQXzFhivhVMEpSXE0Y4A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=/q/Q4y6ab/DuhdpLXSBA9//nauFzjd98lt9HvmG6hoE=; b=eS/CspCCS17eaW/MdjwMan/K2W5usKla/nuMRbdllkbTdd3WQlHGGyXrfxLUxte2mWhr5q1/d4H0zm5X/sDisJporsWc0rnESbAseF5tmrMYAag8aaJ5u4lH9gS2/4evLqByOPPju4Qomu62h8tDbNp1KzWHwO7rDF6URK3oddUiZE9JVqb2WkvAFUunukhqMM3Y7E+dKMDnXReXOcXKyzKPN3Y6S0NuJJjWLhRlXycKqD67oqJEU6/wWqRf9CjExrblj4QkX6jBayQncSk1WCwhA7cxiz3AKGM2xAskSw43irI2bRUZ55qHyXPJQbOiN536q+/3PoL891Lff+X12A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=piap.lukasiewicz.gov.pl; dmarc=pass action=none header.from=piap.pl; dkim=pass header.d=piap.pl; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lukasiewiczgov.onmicrosoft.com; s=selector1-lukasiewiczgov-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=/q/Q4y6ab/DuhdpLXSBA9//nauFzjd98lt9HvmG6hoE=; b=sfmus0UprdqtMnm3mdcTsjAtWTIDILOOVB9XREuY+hMzvr+5t+g4ADxMDn3XSr/oMdFRYNawqfXv2M15evHXQdiYgA5s6mE5uBZOFU79aoR4E2Zk5geaPUxYv6VNNjZlRjHMFS4fHXC/sBXKqv06ZA9x9WjTSAas9NgFidADZj0= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=piap.pl; Received: from VI1P193MB0685.EURP193.PROD.OUTLOOK.COM (2603:10a6:800:155::18) by AS8P193MB2302.EURP193.PROD.OUTLOOK.COM (2603:10a6:20b:44f::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6863.46; Fri, 13 Oct 2023 10:39:11 +0000 Received: from VI1P193MB0685.EURP193.PROD.OUTLOOK.COM ([fe80::bd36:39a7:40e3:c90e]) by VI1P193MB0685.EURP193.PROD.OUTLOOK.COM ([fe80::bd36:39a7:40e3:c90e%4]) with mapi id 15.20.6863.046; Fri, 13 Oct 2023 10:39:11 +0000 From: =?utf-8?Q?Krzysztof_Ha=C5=82asa?= To: Stefan Lengfeld Cc: linux-media , lkml , Dave Stevenson , Oleksij Rempel , Pengutronix Kernel Team , Shawn Guo , Sascha Hauer , Fabio Estevam , NXP Linux Team , linux-i2c@vger.kernel.org Subject: Re: Sony IMX290/462 image sensors I2C xfer peculiarity References: <20231011101553.we3r73xejvqdql5j@porty> <20231012220127.GB27838@stcim.de> Date: Fri, 13 Oct 2023 12:39:09 +0200 In-Reply-To: <20231012220127.GB27838@stcim.de> (Stefan Lengfeld's message of "Fri, 13 Oct 2023 00:01:27 +0200") Message-ID: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: WA2P291CA0010.POLP291.PROD.OUTLOOK.COM (2603:10a6:1d0:1e::16) To VI1P193MB0685.EURP193.PROD.OUTLOOK.COM (2603:10a6:800:155::18) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: VI1P193MB0685:EE_|AS8P193MB2302:EE_ X-MS-Office365-Filtering-Correlation-Id: f212bc5f-a398-4047-a585-08dbcbd8a2c9 X-MS-Exchange-AtpMessageProperties: SA X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:VI1P193MB0685.EURP193.PROD.OUTLOOK.COM;PTR:;CAT:NONE;SFS:(13230031)(39860400002)(366004)(376002)(396003)(136003)(346002)(1800799009)(186009)(64100799003)(451199024)(6506007)(52116002)(6512007)(478600001)(6486002)(26005)(83380400001)(66574015)(316002)(42882007)(7416002)(2906002)(6916009)(54906003)(66476007)(66556008)(5660300002)(41300700001)(8676002)(66946007)(786003)(4326008)(8936002)(83170400001)(38100700002)(38350700002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?eDlSNlBQNVZjSkZScXZMbnEvWFk3aDhUOHpnS1QwUGl5YWlUenFwakE4aEhH?= =?utf-8?B?ZnAyRjlHVWVUMEk3OWNLdHUvZDZhQ3dBbGgxQkdtcTdpYXZwZSs1aDZlOHNu?= =?utf-8?B?aVNHeUhJUDhFQ0trZitKc00rQVBOVGRBcThOb2l4elBMMWYyeWJLR2dDODV0?= =?utf-8?B?NkRJdWVkTit5OFlMTVp5ZTlCeDRGOUV4WVhSSE9TU05pQjlzem5MY1NYaHUv?= =?utf-8?B?SzNCQmcxMEV1SDdWS1k1UmFZMkx2ZEhOcE5GT3NKNDVESkhxWGdNODl1MkIx?= =?utf-8?B?Ujd4VkF2R1pzb1lrM1NEMHMrcnVVWmVSNnBuNGtwTVdsemN2S0dZOWQ0RzNQ?= =?utf-8?B?UDZvVWhBWXJGOGNOcVE3bXZnZ1NIS25lOWtFRzhWUVJEek01bzVTUG50VGlV?= =?utf-8?B?WVlqT2VGR2Zncm8zdGdRaTZ4QmZ4SHpjblR0Z1F0c3ZTSFlkYlQ3UW04Ym96?= =?utf-8?B?cDBXbXdKSzdHR3I3djJQZENDQ0xPS0xYdXNUWlRyMFhYODN1cG1lQXg0Q05w?= =?utf-8?B?N2g3UVVyNTNKRk9Hc2Q2VlhLQ3hrMERvUE9SVlN1TXdxd3FjOXdyU1ZpcS95?= =?utf-8?B?eEp1MDVwNXJNVWxlMW9vZU9nSElNdlVhK1VJclgxNSt6dUJxWS9ZV1ZVY1Bh?= =?utf-8?B?am03NEwyQ3dPNzlobGpKOWdYYjk3WXdCQ0JqOXdQTmM5S1d4ekViUWxFYUpO?= =?utf-8?B?alhibjZOMFNzVHFXWVl2R1FDbGp3d2E1cDlMRFZLOWtzY0dJWnZtVldYMld4?= =?utf-8?B?YWFsUDR2SmxtRFRzTjIyMjJDVXh3ckFJMWxvRy96cTdlWVRCRGlGZ1VQVlgz?= =?utf-8?B?b1o1NTJYN201RTl2eDZmdWQydFFrZkdFNmgxT0RSUmRmWDk4TTVaQmFQeE1m?= =?utf-8?B?TTQ0a09Hejh2S1kydG9EY3dHMXdWSDhlS2Q3eWg4MTdvWm5GN2dqTkxLYXpU?= =?utf-8?B?VHZndXNaMC9MQkxOYW1KOEo5ZjVsRlBIYnR4QXJxN2pMVGV1aS9XWk9COFFF?= =?utf-8?B?N3g3QVVnQURXWWtiQVVROU1BRGQ3RDFxeW16VERpTHEreWhFakJud2ZyazBi?= =?utf-8?B?MEM4OEorellmWXhuZ0RiamVLby94UDE4R0E2eFJLbk4rZGp3MVQ2T3RSOEdn?= =?utf-8?B?Rkt3SFNjWWJLaGllQjRSbzlxTWVMdW0wUVVZUzBMRitMVXhRb1hqem4xeVlz?= =?utf-8?B?NnFQcHM3aklMV1B2ZTVYRVlPUWljU0N6L0lTTGFpWmYvaGpsSnVkZ0hOYVRt?= =?utf-8?B?cUp2M3ZFb0dsU3ZTOEZYcnlab3JQWGZEeWNMQjF1SlNraGVBaUJZaDVkNGNq?= =?utf-8?B?NlRLdlZrN3pzNTdJaHUyOTlPUzcyM2p6MllYSE9SSHJPVUhXZit0dmtBcU41?= =?utf-8?B?cGw4MXYyZ3Zpekt2UmFjL05Tanh0MHJKNGFIbjJrakZhNGpXdGc2OFdGRCtv?= =?utf-8?B?SEFOc0YwVzVyOXRiWUdwMnJ2dzlIdm5LUHFFNHRReGh2RWhNcEtjcWoxN09w?= =?utf-8?B?b1ZZYUNTbWovTFZXMkhUMXNTcW1tWjcyTXBIM2RCZlNXSW1GVlBmSzJtL0Rx?= =?utf-8?B?SFZSdDBtT2JSeXNiTi9RaSsxdE8yZzFaOHFiMGxDeEUwQW1GZWZGa2VxSDJl?= =?utf-8?B?cDVFWFpnR0YvUkV0QmhJT3lucFdaUlZrQ1NYKzZrOXcyU01GL2hVZnZtdzZF?= =?utf-8?B?bEIyWms2KzdnU2dwdFdXQmlPVG5PU0FUQyt3emxnVkMzemZjdFVLL0VZeUJP?= =?utf-8?B?WjJsMGVlK04wLzVBU3hsWVQvWGxuMFhmMHdYNHZsUm1qNW9GNW9vZlhLVnll?= =?utf-8?B?aFNVUFp4bWFkZ3F2VUNpSERhYjJHQlUrL0VTeXJDZ2w2UVJVdVByRXlHTW5Y?= =?utf-8?B?d0tWcEJSdTh0cVBrOGdaMmxUTmcyLzdEV1crNHVOc0FuTkF2aUM1dTBqRUtl?= =?utf-8?B?NHB4c05GWW9qM09EY2xwYU1HZ0RyVXdkbHBGUHlDQytxZVlROVlEc1pIK0pj?= =?utf-8?B?ZWZFd1JzeGo0SnpnVTRLRkxKKzhDWTdvR0V2ZEJQa0FtcWJJb1FsQ2tZSUNU?= =?utf-8?B?Zm1WaXFzZ2hseUJieVo1d3BuRURsM2NIS2lPSFdFK2F0dk1GWXhiQzE2TEtp?= =?utf-8?B?VXJwZmtHR2JzTUEwWXBRM1Nzdk8rTXYvUXBob05sS01JcjAvREdYbVF1TGJS?= =?utf-8?Q?WACJ3cNuFAlwE2jCIWYlzzWXd9hdfLyYNDphWvu3rHZj?= X-OriginatorOrg: piap.pl X-MS-Exchange-CrossTenant-Network-Message-Id: f212bc5f-a398-4047-a585-08dbcbd8a2c9 X-MS-Exchange-CrossTenant-AuthSource: VI1P193MB0685.EURP193.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Oct 2023 10:39:11.0252 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3e05b101-c6fe-47e5-82e1-c6a410bb95c0 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: p2Mx+LKWUrEtPlDH8DIClLugtcFyimSCZM5FdxMEgMCWctdbFiziAF21GpGMfGel69Uw4B/Fw1gh+mbzgtLzqs/evM/yhYDx0S2lmTfBPYIXuVKT+xTA5QTzyo8qAg6my7p3KZrMB5H9i2N5DvDHug== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS8P193MB2302 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Stefan, > Maybe you just hit a corner case or a bug, that can be avoid, in the I2C > device. Maybe check with the manufacturer directly? I don't have direct contact at Sony, I guess I can try to escalate this through the part supplier, but I won't hold my breath. > Do you know the I2C repeated start feature [1]? This allows to batch toge= ther > multiple I2C read/writes in a single transfer. And in the best case, this > transfer is executed in one go without a delay in between. At least in th= e > kernel it's guaranteed that no other driver can go in between with anothe= r > transfer. Sure, imx290.c sensor driver use repeated STARTs. In fact, it only makes things worse. The timeout counter seems to start with the regular START (falling edge of SDA), repeated STARTs don't reset it. After 2^18 + 8 or + 9 MCLK cycles, the sensor simply disconnects from the bus, generating pseudo-STOP if it was in the middle of its 0 bit (0->1 SDA change while SCL high) or starting sending pseudo-1 bits otherwise (0xFF data on read or negative ACK on write). This way repeated START -> longer transfer -> higher probability of failure. Not that it really matters. I don't know about in-sensor race conditions, for example on WRITE to the chip, when the ACK it interrupted by the timeout (this can be detected by the CPU, but not reliably, depending on actual timings). OTOH with my "always use atomic xfers with these sensors" hack to the i.MX I2C driver, it seems to work correctly (at least as far as I2C is concerned). I wonder if we could/should add some special handling of these sensors in the mainline kernel. local_irq_save() and the atomic path do the trick, but it would have to be done in all I2C drivers (or at least in ones used with these sensors). If no other devices need such treatment, well... Everyone can (possibly) use a non-official hack. Thanks for your input, --=20 Krzysztof "Chris" Ha=C5=82asa Sie=C4=87 Badawcza =C5=81ukasiewicz Przemys=C5=82owy Instytut Automatyki i Pomiar=C3=B3w PIAP Al. Jerozolimskie 202, 02-486 Warszawa