Re: [PATCH v2] i2c: stub: Add support for SMBus block commands

From: Jean Delvare
Date: Sun Jul 13 2014 - 11:14:24 EST

On Sun, 13 Jul 2014 08:04:54 -0700, Guenter Roeck wrote:
> On 07/13/2014 12:21 AM, Jean Delvare wrote:
> > Hi Guenter,
> >
> > On Sat, 12 Jul 2014 08:05:49 -0700, Guenter Roeck wrote:
> >> Any idea how we could inject errors ? Error path testing would be quite useful.
> >
> > Good idea. This should probably be done with a sysfs attribute so that
> > it can be turned on and off as desired. Off by default, of course. Some
> > other subsystems already support error injection, you could check how
> > they are doing it, do that we do not diverge needlessly.
> >
> > Do you think there is any value in failing with different error codes,
> > or just -EIO is enough?
> How about writing the error code to return into the attribute ?
> Write anything negative, and it is returned as error. Write 0,
> and the driver works as normal.

This is smart, I like it :)

> > Do you think it should fail all the time when error injection is
> > enabled, or is there a value in having only a certain % of commands
> > fail?
> For my purposes I would want it to fail reliably. We could add some fanciness,
> though: Provide a second attribute which specifies how many operations should
> pass before the first failure.

Let's start simple and just implement what you need.

Jean Delvare
SUSE L3 Support
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