From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [PATCH v2] i2c: stub: Add support for SMBus block commands Date: Sun, 13 Jul 2014 08:04:54 -0700 Message-ID: <53C2A016.2070906@roeck-us.net> References: <1404742983-27303-1-git-send-email-linux@roeck-us.net> <20140708215453.0677d3ed@endymion.delvare> <53BC4F15.9030608@roeck-us.net> <20140712112019.618d8a03@endymion.delvare> <53C14ECD.7050105@roeck-us.net> <20140713092127.4bedfa18@endymion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140713092127.4bedfa18@endymion.delvare> Sender: linux-doc-owner@vger.kernel.org To: Jean Delvare Cc: Wolfram Sang , Randy Dunlap , linux-i2c@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-i2c@vger.kernel.org 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. > 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. Thanks, Guenter