linux-kernel - Re: [PATCH V1 2/2] i2c: tegra: notify transfer-complete after clearing status.

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Message-ID: <20120512130756.GI20673@pengutronix.de>
Date:	Sat, 12 May 2012 15:07:56 +0200
From:	Wolfram Sang <w.sang@...gutronix.de>
To:	Laxman Dewangan <ldewangan@...dia.com>
Cc:	khali@...ux-fr.org, ben-linux@...ff.org, swarren@...dotorg.org,
	olof@...om.net, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH V1 2/2] i2c: tegra: notify transfer-complete after
 clearing status.

On Mon, May 07, 2012 at 12:16:19PM +0530, Laxman Dewangan wrote:
> The notification of the transfer complete by calling complete()
> should be done after clearing all interrupt status.
> This may avoid the race condition of misconfigure the i2c controller
> in multi-core environment.

"may avoid" or "does avoid"? I.e. does it fix any bug that really
occured? Then I'd add a stable tag.

So far, applied to next.

>  	if (status & I2C_INT_PACKET_XFER_COMPLETE) {
>  		BUG_ON(i2c_dev->msg_buf_remaining);
>  		complete(&i2c_dev->msg_complete);
>  	}

Side note: If you see a way to handle the BUG invocations more
gracefully, that would be appreciated.

Thanks,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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