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From: Marek Vasut <marex-ynQEQJNshbs@public.gmane.org>
To: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Cc: "Uwe Kleine-König"
	<u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>,
	"Fabio Estevam"
	<festevam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH] i2c: mxs: disable QUEUE when sending is done
Date: Sun, 29 Apr 2012 11:11:13 +0200	[thread overview]
Message-ID: <201204291111.13333.marex@denx.de> (raw)
In-Reply-To: <20120429084324.GA3001-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

Dear Wolfram Sang,

> > > > I am wondering if we should only set QUEUE_RUN bit here.
> > > 
> > > I didn't check the manual, but I guess writing to MXS_I2C_QUEUECTRL_CLR
> > > just clears the QUEUE_RUN bit and nothing else?!
> > 
> > I think the RUN bit will be cleared by the controller anyway, so this
> > patch is pointless.
> 
> How do you get this idea? Given 27.3.2 and our experiences, I'd be very
> surprised. Try putting the system under heavy load without this patch
> and you'll see that FIFOs might be sent half filled when interrupted
> while filling.

All right, I won't argue here ;-)

Best regards,
Marek Vasut

WARNING: multiple messages have this Message-ID (diff)
From: marex@denx.de (Marek Vasut)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] i2c: mxs: disable QUEUE when sending is done
Date: Sun, 29 Apr 2012 11:11:13 +0200	[thread overview]
Message-ID: <201204291111.13333.marex@denx.de> (raw)
In-Reply-To: <20120429084324.GA3001@pengutronix.de>

Dear Wolfram Sang,

> > > > I am wondering if we should only set QUEUE_RUN bit here.
> > > 
> > > I didn't check the manual, but I guess writing to MXS_I2C_QUEUECTRL_CLR
> > > just clears the QUEUE_RUN bit and nothing else?!
> > 
> > I think the RUN bit will be cleared by the controller anyway, so this
> > patch is pointless.
> 
> How do you get this idea? Given 27.3.2 and our experiences, I'd be very
> surprised. Try putting the system under heavy load without this patch
> and you'll see that FIFOs might be sent half filled when interrupted
> while filling.

All right, I won't argue here ;-)

Best regards,
Marek Vasut

  parent reply	other threads:[~2012-04-29  9:11 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-27 14:23 [PATCH] i2c: mxs: disable QUEUE when sending is done Wolfram Sang
2012-04-27 14:23 ` Wolfram Sang
     [not found] ` <1335536631-28202-1-git-send-email-w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2012-04-27 14:51   ` Fabio Estevam
2012-04-27 14:51     ` Fabio Estevam
     [not found]     ` <CAOMZO5A1_Z7T5md61OJWmXbx2qCjFEByjyGvjhxqhfxzwfLEVQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-04-28 10:26       ` Uwe Kleine-König
2012-04-28 10:26         ` Uwe Kleine-König
     [not found]         ` <20120428102601.GO20039-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2012-04-28 13:33           ` Marek Vasut
2012-04-28 13:33             ` Marek Vasut
     [not found]             ` <201204281533.35277.marex-ynQEQJNshbs@public.gmane.org>
2012-04-29  8:43               ` Wolfram Sang
2012-04-29  8:43                 ` Wolfram Sang
     [not found]                 ` <20120429084324.GA3001-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2012-04-29  9:11                   ` Marek Vasut [this message]
2012-04-29  9:11                     ` Marek Vasut

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