Re: Which AMD CPUs are supported -- temperature

The step size of 1/8 degree C/K is documented in the public BKDG (prior to
17h) and PPR (17h+) documents available on AMD’s website, at least for
relatively recent models. I don’t know about very old models (really
anything older than 17h, although I’ve looked at the 15h docs some).

Best,
Conrad

On Wed, Feb 12, 2020 at 23:22 Peter Jeremy <peter_at_rulingia.com> wrote:

> On 2020-Feb-12 15:23:51 -0500, mike tancsa <mike_at_sentex.net> wrote:
> >Not sure about the older Athlon CPUs, but the 2 generations of Ryzen's I
> >have seem correct as well as an APU
> >
> >CPU: AMD GX-412TC SOC                                (998.17-MHz K8-class
> CPU)
>
> OTOH, I'm not confident about temperatures on my APU.  The publicly
> available data just says that the SoC reports "a temperature on its own
> scale" relative to a Tctl_max which "is specified in the power and thermal
> data sheet" (that I have been unable to locate).  Everyone seems to assume
> that the step size is 0.125K but I haven't found that publicly documented
> anywhere.  The AMD Product Brief states that the maximum temperature is
> 90°C but using that as Tctl_max gives me temperature readings that don't
> look right.
>
> >And on a fanless APU
> >
> ># sysctl -a dev.cpu.0.temperature
> >dev.cpu.0.temperature: 62.6C
> >
> ># sysctl -a dev.amdtemp.0.core0.sensor0
> >dev.amdtemp.0.core0.sensor0: 63.1C
>
> At what ambient temperature?  I see a similar value from my (idle) APU3
> but don't believe the (implied) ~35K junction-to-ambient difference.
>
> --
> Peter Jeremy
>