Re: [PATCH] eeprom: at24: Add support for large EEPROMs connected to SMBus adapters

From: Guenter Roeck
Date: Thu Mar 19 2015 - 13:43:26 EST


On Thu, Mar 19, 2015 at 09:16:21AM +0100, Wolfram Sang wrote:
>
> > I don't call that multi-master, though, so I guess we may have a bit of a
> > terminology problem.
>
> This is definately not a multi-master issue, I agree. It is just
> another issue I saw when thinking about your patch thoroughly again.
>
> > I'll see what I can come up with, but I am not sure if I'll find the time
> > before the 4.1 commit window opens. Company has a working solution (kind of),
> > so now I'll have to do this on my own time ;-).
>
> But their solution is buggy and needs a fix! :)
>
Turns out this is really easy to reproduce. One process reads
the eeprom over and over again, another runs i2cdump in a loop,
and voila ... lots of corruptions. Scary, especially considering
how wide-spread this kind of i2c access is in the kernel.

Guenter
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