Re: [PATCH] i8k: Add support for temperature sensor labels

Pali Rohár
2014-11-30T18:00:52Z

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On Sunday 30 November 2014 18:54:21 Guenter Roeck wrote:
> On 11/30/2014 09:44 AM, Pali Rohár wrote:
> > On Sunday 30 November 2014 17:00:18 Guenter Roeck wrote:
> >> On 11/30/2014 01:53 AM, Pali Rohár wrote:
> >> [ ... ]
> >>
> >>>>> Original Dell DOS executable ignores all temperature
> >>>>> sensors if type SMM function fails (if I decoded and
> >>>>> understand that DOS assembler code correctly). So maybe
> >>>>> we should do same...
> >>>>>
> >>>>> But because our i8k.c code ignores sensor only if it
> >>>>> returns invalid temperature, there could be possible
> >>>>> regression that on same machines type SMM function is
> >>>>> not implemented or not working...
> >>>>>
> >>>>> What do you think?
> >>>>
> >>>> Tested with XPS13, Studio 1555 (with GPU), and XPS M140.
> >>>> Reading the type works with all of them. The Studio 1555
> >>>> reports the GPU temperature in temp4. The M140 is quite
> >>>> old (about 10 years), so I guess we can be reasonably
> >>>> sure that all laptops currently in use support reporting
> >>>> the type.
> >>>
> >>> Good. Then I will split this patch into two parts. One
> >>> which adds labels and one which change init code to
> >>> register only those sensors which have valid type.
> >>
> >> Ok.
> >>
> >>>> Do you know what is returned for the type if the GPU is
> >>>> turned off on a system with GPU ? I think that is the
> >>>> only open question.
> >>>
> >>> Yes, on my E6440 in both cases when GPU is turned off and
> >>> on is returned same type (GPU). So this does not help us.
> >>
> >> Unless I misunderstand you, it does help us; it simplifies
> >> sensor detection since we don't have to handle the special
> >> case that the GPU is turned off anymore.
> >>
> >> Thanks,
> >> Guenter
> >
> > Yes, sensor type is returned always correctly, so this is
> > good.
> >
> > I mean that it cannot be used for detecting if GPU is turned
> > on or off.
>
> Yes, but that is a good thing, because it helps us figuring
> out if the GPU sensor should be enabled or not during probe,
> so we no longer need to try reading the temperature, and we
> no longer have to handle the case of "GPU supported, but
> turned off" during probe.
>
> When reading the temperature, returning -ENODATA if the GPU
> is turned off is the best we can do.
>
> Thanks,
> Guenter

Yes, you are right. I will create new patches.

--
Pali Rohár
pali.rohar@gmail.com

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