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From: Esben Haabendal <esben.haabendal@gmail.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: linux-i2c@vger.kernel.org,
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
Date: Mon, 09 Jul 2018 11:22:31 +0200 [thread overview]
Message-ID: <87tvp8ahm0.fsf@gmail.com> (raw)
In-Reply-To: <20180705063229.sr6jplg63ybyzxta@pengutronix.de> ("Uwe =?utf-8?Q?Kleine-K=C3=B6nig=22's?= message of "Thu, 5 Jul 2018 08:32:29 +0200")
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> writes:
> 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?
It should fix the problem.
/Esben
next prev parent reply other threads:[~2018-07-09 9:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20180523095623.3347-1-esben.haabendal@gmail.com>
2018-05-23 9:56 ` [PATCH 1/4] i2c: imx: Fix reinit_completion() use Esben Haabendal
2018-07-04 7:03 ` Uwe Kleine-König
2018-07-09 9:20 ` Esben Haabendal
2018-05-23 9:56 ` [PATCH 2/4] i2c: imx: Fix race condition in dma read Esben Haabendal
2018-07-05 6:32 ` Uwe Kleine-König
2018-07-09 9:22 ` Esben Haabendal [this message]
2018-05-23 9:56 ` [PATCH 3/4] i2c: imx: Simplify stopped state tracking Esben Haabendal
2018-05-23 9:56 ` [PATCH 4/4] arm: dts: ls1021a: Enable I2C DMA support Esben Haabendal
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