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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1938BC4332F for ; Fri, 16 Dec 2022 11:03:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=0Zb8fS4Zd0QQP0iKL4+Q3uxTS/RAbnKL1z+asnG1GuY=; b=BW5CxhiVSnRb8/ ZC4zjvVOcC5UbjZy6fN7/qXFLO7gNh02McMJ1GC+jxV1ejAhfArKhnxBJiwZWI+0Eqz10FDrYoDi4 OGi7wrkoNjyvt/+Yrn4XWPIQWoHnjQpxDOkptKDnHWwkcLxaoFrZODMyeltg++J09E7HrvuJ0TmQt ir3d3c6NxskWwtmoaeSRBbE7JDlsSULRx4kGonF1aaP7fL3+DHJwla9YMvNkxU5tu9tO3LEeL0nEa YqPvRlfYRBqAUrcMX6R20ReL3k2mb4G3rTMecSTR+Lx12yMqwGZY3XjSImDqV1CuZiavNBggjWems A2MY4S/I2jbmhyk7isfw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p68UI-00EJBI-7U; Fri, 16 Dec 2022 11:02:46 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p68UD-00EJ3V-Ed for linux-arm-kernel@lists.infradead.org; Fri, 16 Dec 2022 11:02:43 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1p68U0-0001Mb-Uw; Fri, 16 Dec 2022 12:02:28 +0100 Received: from ore by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1p68Tz-0003Yt-O1; Fri, 16 Dec 2022 12:02:27 +0100 Date: Fri, 16 Dec 2022 12:02:27 +0100 From: Oleksij Rempel To: Primoz Fiser Cc: Marco Felsch , 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 Subject: Re: [PATCH] i2c: imx: increase retries on arbitration loss Message-ID: <20221216110227.GA12327@pengutronix.de> References: <20221216084511.2576786-1-primoz.fiser@norik.com> <20221216094518.bevkg5buzu7iybfh@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221216_030241_526734_9ADB48CC X-CRM114-Status: GOOD ( 23.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Dec 16, 2022 at 11:41:08AM +0100, Primoz Fiser wrote: > 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. https://lore.kernel.org/all/Ys1bw9zuIwWS+bqw@shikoro/ -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel