Re: [PATCH v3] hwmon: (k10temp) Enable AMD3255 Proc to show negative temperature

[Guenter Roeck]

On 6/19/23 12:58, Limonciello, Mario wrote:
> On 6/19/2023 2:48 PM, Guenter Roeck wrote:
> > On 6/19/23 11:53, Limonciello, Mario wrote:
> > [ ,,, ]
> >
> > > So Pinnacle Ridge and Summit Ridge (Zen/Zen+) have model_id_str values of 'B1' and 'B2'.
> > > I think we should be able to detect those and only avoid showing the negative values when:
> > >
> > > * Family 17h
> > > * Model > 0x00
> > > * Model <= 0x0f
> > > * Model ID str B1 or B2
> >
> > Threadripper 1950X model string is "AMD Ryzen Threadripper 1950X 16-Core Processor".
> > Not sure where B1 or B2 is seen, but it is not in the model string.
> >
> > Guenter
> Sorry; I thought you were talking about desktop parts and didn't realize it was a Threadripper
> part that prompted all of this.
>
> I looked at the old commit aef17ca127, and it seems that this is tied to the usage of some
> overclocking knobs offered by some BIOS vendors.

Correct.

> As an idea to avoid the initial issue and all these hacks; what about changing the logic to
> compare the calculated temperature against the max temperature?  If it's greater than the max
> THEN set it to zero.

No, that won't work anymore. In the old code, negative temperatures were displayed as large
positive temperatures. This was changed later, and temperatures are now reported as
negative temperatures.

Is there a way to detect if those overclocking knobs are set ? Alternatively, we could\
possibly just check if the CPU is a Threadripper and limit the hack to Threadripper CPUs.

Thanks,
Guenter