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Date:   Thu, 5 Jul 2018 08:32:29 +0200
From:   Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= 
        <u.kleine-koenig@pengutronix.de>
To:     Esben Haabendal <esben.haabendal@gmail.com>
Cc:     linux-i2c@vger.kernel.org, Esben Haabendal <eha@deif.com>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Lucas Stach <l.stach@pengutronix.de>,
        Phil Reid <preid@electromag.com.au>,
        Linus Walleij <linus.walleij@linaro.org>,
        Clemens Gruber <clemens.gruber@pqgruber.com>,
        Wei Jinhua <wei.jinhua1@zte.com.cn>,
        Michail Georgios Etairidis <m.etairidis@beck-ipc.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] i2c: imx: Fix race condition in dma read
Message-ID: <20180705063229.sr6jplg63ybyzxta@pengutronix.de>
References: <20180523095623.3347-1-esben.haabendal@gmail.com>
 <20180523095623.3347-3-esben.haabendal@gmail.com>
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On Wed, May 23, 2018 at 11:56:21AM +0200, Esben Haabendal wrote:
> From: Esben Haabendal <eha@deif.com>
> 
> This fixes a race condition, where the DMAEN bit ends up being set after
> I2C slave has transmitted a byte following the dummy read.  When that
> happens, an interrupt is generated instead, and no DMA request is generated
> to kickstart the DMA read, and a timeout happens after DMA_TIMEOUT (1 sec).
> 
> Fixed by setting the DMAEN bit before the dummy read.

Does this fix the problem or just narrow the race window?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |