Re: mmiotracer hangs the system

[karol herbst]

2016-08-19 17:35 GMT+02:00 Andy Shevchenko <andy.shevchenko@xxxxxxxxx>:
> On Fri, Aug 19, 2016 at 6:08 PM, karol herbst <karolherbst@xxxxxxxxx> wrote:
>> 2016-08-19 15:02 GMT+02:00 Andy Shevchenko <andy.shevchenko@xxxxxxxxx>:
>>> On Fri, Aug 19, 2016 at 1:35 PM, karol herbst <karolherbst@xxxxxxxxx> wrote:
>>>> is there any update on that issue I missed somehow? I really don't
>>>> want to leave the mmiotracer in a state, where it breaks something
>>>> while fixing other issues.
>>>
>>> No updates. I'm busy right now with more priority tasks and revert
>>> works for me. Issue is reproducible in my case 100%.
>>>
>>
>> Is there something I could do with a "normal" haswell desktop system
>> to reproduce this issue?
>
> Try LPSS UART device(s)
>

isn't this a skylake thing? Because my CPU and motherboard is a bit
older than this.

>>
>> I'll try to play around the next days a bit and maybe I find something
>> that works out here as well. It seems to be related to
>> unmapping-mapping cycles.
>
> That is the only thing I would think of.
>
>>
>> Because if this only happens with the pwm-lpss driver,
>
> It has nothing to do with pwm-lpss since it's a HS UART and served by
> intel-lpss driver.
>
>> it may be
>> really troublesome to debug, because I don't really know the code that
>> well to be sure where the issue might be.
>>
>>> So, I would able to attach dmesg in case it would be helpful.
>>> Otherwise tell me exact instructions how to debug the issue.
>>>
>>> Here you are:
>>> http://pastebin.com/raw/VfTZENt7
>>>
>>>> But for now, without being able to even reproduce the issue, I can't
>>>> really do much, because the code in the current state looks sane to
>>>> me. Maybe this case includes the mmiotracer cleaning things up and
>>>> arms new region for mmiotracing and that's why it fails? Besides that,
>>>> I have no idea and no way to reproduce this, so I can't help this way.
>>>
>>> Maybe. First thing happened is iounmap().
>
>
> --
> With Best Regards,
> Andy Shevchenko