[PATCH 0/3] Thermal reset support in PMC

Mikko Perttunen mperttunen at nvidia.com
Wed Aug 13 03:59:00 PDT 2014

On 13/08/14 13:53, Thierry Reding wrote:
> * PGP Signed by an unknown key
> On Wed, Aug 13, 2014 at 01:41:52PM +0300, Mikko Perttunen wrote:
>> On 13/08/14 13:36, Thierry Reding wrote:
>>>> Old Signed by an unknown key
>>> On Wed, Aug 13, 2014 at 12:52:22PM +0300, Mikko Perttunen wrote:
>>>> On 13/08/14 11:57, Thierry Reding wrote:
>>>>>> Old Signed by an unknown key
>>>>> On Wed, Aug 13, 2014 at 11:42:53AM +0300, Mikko Perttunen wrote:
>>>>>> On 13/08/14 11:12, Mikko Perttunen wrote:
>>>>>>> On 13/08/14 11:07, Thierry Reding wrote:
>>>>>>>>> Old Signed by an unknown key
>>>>>>>> On Tue, Aug 05, 2014 at 11:12:57AM +0300, Mikko Perttunen wrote:
>>>>>>>>> Hi,
>>>>>>>>> this series adds support for hardware-triggered thermal reset to the PMC
>>>>>>>>> driver. Namely, it adds device tree properties for specifying the I2C
>>>>>>>>> command to be sent when thermtrip is triggered. It is to be noted
>>>>>>>>> that thermtrip won't be ever triggered without a soctherm driver to
>>>>>>>>> calibrate the sensors, but I'll follow up with that patch.
>>>>>>>>> pmc.c required some juggling around to make the match data usable in
>>>>>>>>> probe, since I didn't want to put the code into the initcall either, since
>>>>>>>>> the soctherm driver won't be initialized by that point anyway.
>>>>>>>>> Series tested on Jetson-TK1. Should work on Tegra30 and Tegra114 too.
>>>>>>>> Can you describe the procedure used to test this? We currently have a
>>>>>>>> bunch of features in Tegra that some people have tested at some point
>>>>>>>> during development but the test procedures never got documented. That
>>>>>>>> means whenever we want to test something we need to go and reinvent a
>>>>>>>> bunch of tests after the fact.
>>>>>>>> So what I'd like to start doing is collect tests (preferably in some
>>>>>>>> scripted way) so that they can be kept in a repository that people can
>>>>>>>> easily clone and run on devices.
>>>>>>>> Could you provide something like that for thermtrip?
>>>>>>> Sure. I'll see if I can make a just a test script or if a local patch is
>>>>>>> needed to test. Btw, I also have a pretty nice test script for EMC
>>>>>>> ready, and I agree that such a repository would be very nice.
>>>>>> Here is a test program. It it works, the device with immediately shut down.
>>>>>> https://gist.github.com/cyndis/66126c9c176b5f94a76f
>>>>> Is there a way to set the trip temperature without going through
>>>>> /dev/mem? I'd expect the device to have a sysfs interface of some
>>>>> sort.
>>>> The thermtrip "device" isn't currently exposed in any way. If it were
>>>> exposed, I suppose it would be exposed as thermal zone devices, each with
>>>> one trip point. Even then, the thermal framework doesn't really support this
>>>> properly; none of the trip point types really apply to this kind of trip
>>>> point, and x86 systems don't expose their trips either.
>>> Okay. The reason why I asked is because I'm not sure yet that having C
>>> programs in the test suite would be good, so having something that's
>>> easily scriptable would be preferred.
>> I agree. Looks like Python's stdlib has mmap support, so maybe we could use
>> that.
> Yes, possibly. It still means that somebody needs to have some kind of
> advanced scripting available to test this. While having a testsuite is
> useful, it would still be nice to occasionally be able to test things
> with just simple shell commands.
>>>> Anyway, since debugging is pretty much the only use case for modifying
>>>> the trip temperature, I thought adding the tz_devices would be a bit
>>>> overkill.
>>> An alternative could be a file in debugfs.
>> True, though there's the "don't expose dangerous stuff in debugfs" argument
>> against that. I don't really have problem with it, though.
>> Although in this case I think the script approach would be good enough.
> I've said this before and I don't think "dangerous stuff in debugfs" is
> a valid argument. You need superuser privileges to access debugfs, and
> if you have such privileges you can do pretty much what you want (run
> the test program you posted for example).

I agree with you completely. I guess I can add a debugfs entry to the 
soctherm driver, probably in a separate patch once the original series 
is in. It is then up to the thermal maintainers whether they agree with 
us or not.

> Thierry
> * Unknown Key
> * 0x7F3EB3A1

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