Re: Which AMD CPUs are supported -- temperature

From: Peter Jeremy <peter_at_rulingia.com>
Date: Thu, 13 Feb 2020 18:22:12 +1100
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

Received on Thu Feb 13 2020 - 06:22:51 UTC

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