From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shubhrajyoti Datta Subject: Re: [PATCH 1/3] i2c: Revert "i2c: xiic: Do not reset controller before every transfer" Date: Tue, 17 Nov 2015 19:58:16 +0530 Message-ID: References: <1447681325-30914-1-git-send-email-lars@metafoo.de> <564AD886.3060108@metafoo.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-qk0-f170.google.com ([209.85.220.170]:33470 "EHLO mail-qk0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753101AbbKQO2R (ORCPT ); Tue, 17 Nov 2015 09:28:17 -0500 Received: by qkas77 with SMTP id s77so3211219qka.0 for ; Tue, 17 Nov 2015 06:28:16 -0800 (PST) In-Reply-To: <564AD886.3060108@metafoo.de> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Lars-Peter Clausen Cc: Wolfram Sang , Shubhrajyoti Datta , linux-i2c@vger.kernel.org On Tue, Nov 17, 2015 at 1:04 PM, Lars-Peter Clausen wrote: > On 11/17/2015 06:17 AM, Shubhrajyoti Datta wrote: >> On Mon, Nov 16, 2015 at 7:12 PM, Lars-Peter Clausen wrote: >>> Commit d701667bb331 ("i2c: xiic: Do not reset controller before every >>> transfer") removed the reinitialization of the controller before the start >>> of each transfer. Apparently this change is not safe to make and the commit >>> results in random I2C bus failures. >> >> Which is the platform and the ip version that you saw the issue. >> Did you see the issue with read and write as well? > > The IP version is the axi-iic v2.0 Revision 8. I've tested this on a few > platforms, custom ones and standard ones and I could reproduce it on most. > One of them was on the ZED board. The one where I couldn't reproduce it was > the ZC706. But that doesn't necessarily mean it doesn't happen there, just > that it is not triggered by the testcase. All the boards having the same version of the ip is what I have understood. Thanks for the info I will try to reproduce the issue. > > The problem is that it is random corruption, Of registers? > so some I2C devices might start > to behave strangely at some point. The only good more or less reliable way > to reproduce it that I found was to run i2cdetect a couple of times and at > least one of them will produce strange behavior. > I will try to reproduce the issue at my end thanks.