Re: [PATCH v2 2/2] ARM: dts: at91: disable the nxp,se97b SMBUS timeout on the TSE-850

Guenter Roeck
2017-11-30T21:17:45Z

On Thu, Nov 30, 2017 at 07:46:09PM +0100, Peter Rosin wrote:
> On 2017-11-30 18:26, Alexandre Belloni wrote:
> > On 30/11/2017 at 09:16:38 -0800, Guenter Roeck wrote:
> >> On Wed, Nov 29, 2017 at 09:56:29PM +0100, Alexandre Belloni wrote:
> >>> On 29/11/2017 at 12:53:11 -0800, Guenter Roeck wrote:
> >>>> On Mon, Nov 27, 2017 at 05:31:01PM +0100, Peter Rosin wrote:
> >>>>> The I2C adapter driver is sometimes slow, causing the SCL line to
> >>>>> be stuck low for more than the stipulated SMBUS timeout of 25-35 ms.
> >>>>> This causes the client device to give up which in turn causes silent
> >>>>> corruption of data. So, disable the SMBUS timeout in the client device.
> >>>>>
> >>>>> Signed-off-by: Peter Rosin <peda@axentia.se>
> >>>>
> >>>> Acked-by: Guenter Roeck <linux@roeck-us.net>
> >>>>
> >>>> I assume this will be sent upstream through an arm tree.
> >>>>
> >>>
> >>> Yes, I'm applying it right now.
> >>>
> >> Are you going to apply the patch for 4.15, or queue it up for 4.16 ?
> >> I have been arguing with myself if this is a feature or a bug fix.
> >> So far I queued the driver change up for 4.16, but I am open to
> >> applying it to 4.15. Any thoughts ?
> >>
> >
> > I was wondering that myself. I'm open to have it as a fix in 4.15. Or
> > maybe Peter can send the series to stable if he needs it in 4.14.
> >
> > Peter, what do you think/want?
>
> TL;DR Either way is fine.
>
> I think it's a bugfix; it fixes real problems where the application
> misbehave due to faulty content when reading from an eeprom. I'm
> expecting to make a new release for the hw in question RSN and these
> are the only local patches. So, it would be nice if they made it to
> 4.14.x before my release happens. However, it's not like it's difficult
> to rebase the patches should that backport not happen or take too long.
>
Good enough for me. I'll send it as a fix for v4.15, with Cc: stable.

Guenter

> The badness started to happen much more frequently due to some timing
> difference affecting the i2c bus driver, but in theory it's a problem
> that has been there from the start. I have just not noticed it before...
>
> Cheers,
> Peter
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