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Date: Fri, 13 Oct 2017 14:29:35 +0100
From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Peter Rosin <peda@axentia.se>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>
Subject: Re: Sluggish AT91 I2C driver causes SMBus timeouts
Message-ID: <20171013142935.14ef302e@alans-desktop>
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On Thu, 12 Oct 2017 13:35:17 +0200
Peter Rosin <peda@axentia.se> wrote:

> Hi!
> 
> I have encountered an "interesting" bug. It silently corrupts data
> and is generally nasty...
> 
> On an I2C bus, driven by the at91 driver and DMA (an Atmel
> sama5d31 chip), I have an 256 byte eeprom (NXP SE97BTP). I'm using
> Linux v4.13.

If your force the transfer to PIO does it behave ? Does the controller in
fact need to siwtch to PIO for SMBUS ?

Alan