Re: [PATCH v1] i2c: imx: Retry transfer on transient failure

Francesco Dolcini
2022-07-15T11:45:35Z

On Fri, Jul 15, 2022 at 10:34:00AM +0200, Uwe Kleine-König wrote:
> On Fri, Jul 15, 2022 at 09:24:32AM +0200, Francesco Dolcini wrote:
> > On Fri, Jul 15, 2022 at 08:49:31AM +0200, Uwe Kleine-König wrote:
> > > Unless you have a multi-controller setup an arbitration loss is a
> > > problem with the signal integrity. And increasing the retry count is
> > > only a work around.
> > Fair enough.
> >
> > 2. We do have an I2C bus recovery mechanism implemented to recover from
> > a stuck bus, isn't this a workaround as retrying on arbitration lost in a
> > non-multimaster setup?
>
> It depends, if you do it to recover after a transfer failure, it would
> indeed consider it a work around covering the real problem. But
> sometimes there is no practical way around such work arounds. I happens
> from time to time that the reason for problem is known, but fixing the
> hardware is no option, then you need such workrounds. (This applies to
> both, retrying the transfers and resetting the bus.)

And here I am back to square one, to the original reason we did this
change for :-) I feel like we do not want to merge this now because I
cannot prove/explain the exact details of the issue this is trying to
workaround. Not because _is_ a workaround :-).

Fair enough, thanks Oleksij and Uwe for the valuable discussion.

Francesco