[lkml]   [2017]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] hwmon: pmbus: Make reg check and clear faults functions return errors
On 09/07/2017 06:02 PM, Andrew Jeffery wrote:
> On Thu, 2017-09-07 at 17:27 -0700, Guenter Roeck wrote:
>> On 09/07/2017 08:22 AM, Andrew Jeffery wrote:
>>> On Thu, 2017-09-07 at 06:40 -0700, Guenter Roeck wrote:
>>>> On 09/06/2017 04:32 PM, Andrew Jeffery wrote:
>>>>>> Guess I need to dig up my eval board and see if I can reproduce the problem.
>>>>>> Seems you are saying that the problem is always seen when issuing a sequence
>>>>>> of "clear faults" commands on multiple pages ?
>>>>> Yeah. We're also seeing bad behaviour under other command sequences as well,
>>>>> which lead to this hack of a work-around patch[1].
>>>>> I'd be very interested in the results of testing against the eval board. I
>>>>> don't have access to one and it seems Maxim have discontinued them.
>>>> Do you have a somewhat reliable means to reproduce the problem ?
>>> It seems we hit a bunch of problems by just continually
>>> binding/unbinding the driver, if you don't apply that hacky oneshot
>>> retry patch. We can hit problems (in our design?) with something like:
>>> # cd /sys/bus/i2c/drivers/max31785; \
>>> echo $addr > unbind; \
>>> while echo $addr > bind; \
>>> do echo $addr > unbind; echo -n .; done;
>>> It should hit issues covered by this patch, as the register checks are
>>> used in the operations used by probe.
>> Hmm ... I didn't use your driver but my prototype driver which also supports
>> temperature and voltage attributes, so if anything it should create more
>> stress on the chip.
> I did add the temp and voltage attributes...
> Any chance you can give mine a try? I don't know what I would have done
> to invoke this kind of behaviour, so it would be useful to know whether
> or not it happens with one driver but not the other.

Will do.

>> No error so far, after running the script for a couple
>> of minutes. How long does it take for errors to appear, and how do I see
>> that there is an error ?
> I'm seeing failures after anything from a handful of bind/unbinds, to
> hundreds of bind/unbinds. It seems to vary.
>> Does the driver fail to instantiate ?
> Typically probe fails so the loop exits. It usually gets -EIO and the
> shell spits out "No such device".
> Thanks for testing, it's a useful data point for us hunting down the
> source of our problems.
I aborted the test after ~2,500 loops without error.


 \ /
  Last update: 2017-09-08 03:27    [W:0.035 / U:4.400 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site