Re: [PATCH 1/3] i2c: Revert "i2c: xiic: Do not reset controller before every transfer"

[Shubhrajyoti Datta <shubhrajyoti.datta@gmail.com>]

On Tue, Nov 17, 2015 at 1:04 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 11/17/2015 06:17 AM, Shubhrajyoti Datta wrote:
>> On Mon, Nov 16, 2015 at 7:12 PM, Lars-Peter Clausen <lars@metafoo.de> 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.