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 76E24C4167B for ; Fri, 16 Dec 2022 10:41:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230014AbiLPKlR (ORCPT ); Fri, 16 Dec 2022 05:41:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230193AbiLPKlO (ORCPT ); Fri, 16 Dec 2022 05:41:14 -0500 Received: from cpanel.siel.si (cpanel.siel.si [46.19.9.99]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A132F09; Fri, 16 Dec 2022 02:41:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=norik.com; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=QkE6cvAGTPArZRIQb5KHMBKk1af+ie9psS4oH/B3U4Q=; b=GhspP+XWxgi6fXsKUhROMbA1yF v/jCVu02cfZOHjib/20VZ5E+IahOs27Baj9nQBkRvDwRRWwGNpbgYWnq5rRXSTUtghLV5afZkyw9o gik7t7DIhRVsNO5ewNcWMzrZj/JsvBD60/svyssBij/qFGVdD1z8bhsRfRakOkskVlNmJyZt9ZMWv 70p4LqLMKUo3BT26cQRT8mFY7mQ++AbPJQjQu/kLetQeEOLGhIRjoyxJDNK19qfNn6aadkqzpt9qv OGLXn9lfjkgPWpl/qE9TUXM1eiRfUO58+KgjKzlme/MQvLQX9HMYWEIyyWreybjmxaIpIkiVHUWEW unojokkw==; Received: from 89-212-21-243.static.t-2.net ([89.212.21.243]:49226 helo=[192.168.69.116]) by cpanel.siel.si with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.95) (envelope-from ) id 1p689C-005DG8-32; Fri, 16 Dec 2022 11:41:05 +0100 Message-ID: Date: Fri, 16 Dec 2022 11:41:08 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH] i2c: imx: increase retries on arbitration loss Content-Language: en-US To: Marco Felsch Cc: Oleksij Rempel , Pengutronix Kernel Team , Shawn Guo , Sascha Hauer , Fabio Estevam , NXP Linux Team , linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, upstream@lists.phytec.de References: <20221216084511.2576786-1-primoz.fiser@norik.com> <20221216094518.bevkg5buzu7iybfh@pengutronix.de> From: Primoz Fiser In-Reply-To: <20221216094518.bevkg5buzu7iybfh@pengutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - cpanel.siel.si X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - norik.com X-Get-Message-Sender-Via: cpanel.siel.si: authenticated_id: primoz.fiser@norik.com X-Authenticated-Sender: cpanel.siel.si: primoz.fiser@norik.com X-Source: X-Source-Args: X-Source-Dir: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Marco, On 16. 12. 22 10:45, Marco Felsch wrote: > Hi Primoz, > > On 22-12-16, Primoz Fiser wrote: >> By default, retries value is set to 0 (no retries). Set retries to more >> sensible value of 3 to allow i2c core to re-attempt transfer in case of >> i2c arbitration loss (i2c-imx returns -EAGAIN errno is such case). > > apart the fact that the number of retries vary a lot and so the client > driver behaviour can vary a lot which is not good IMHO, why do you think > that 3 is a sufficient number? IMHO it is better than leaving it at 0 (no retries)? Setting it to sensible value like 3 will at least attempt to make transfer in case arbitration-loss occurs. > > If an arbitration loss happen, why do you think that retrying it 3 times > changes that? I our case, setting retries to non-zero value solves issues with PMIC shutdown on phyboard-mira which in some rare cases fails with "Failed to shutdown (err = -11)" (-EAGAIN). To me it makes common sense retries is set to non-zero value especially for such rare conditions/situations. BR, Primoz > > Regards, > Marco > > >> >> Signed-off-by: Primoz Fiser >> --- >> drivers/i2c/busses/i2c-imx.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c >> index cf5bacf3a488..6a5694cfe1cc 100644 >> --- a/drivers/i2c/busses/i2c-imx.c >> +++ b/drivers/i2c/busses/i2c-imx.c >> @@ -1478,6 +1478,7 @@ static int i2c_imx_probe(struct platform_device *pdev) >> i2c_imx->adapter.dev.parent = &pdev->dev; >> i2c_imx->adapter.nr = pdev->id; >> i2c_imx->adapter.dev.of_node = pdev->dev.of_node; >> + i2c_imx->adapter.retries = 3; >> i2c_imx->base = base; >> ACPI_COMPANION_SET(&i2c_imx->adapter.dev, ACPI_COMPANION(&pdev->dev)); >> >> -- >> 2.25.1 >> >> >>