Re: Which AMD CPUs are supported -- temperature

On Thu, 13 Feb 2020 18:22:12 +1100 Peter Jeremy peter_at_rulingia.com said

> 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.
I've read that (most?) of the Intel CPUs (everything since "core" versions)
has a copy of MINIXv3 on them _at_ ring -3. Does/could the AMD System Management
Network provide any *additional* clues?
And *why* won't AMD provide more *definitive* specs? Hoping consumers "cook"
their (A|C)PUs and ultimately buy more of their product?

--Chris
> 
> -- 
> Peter Jeremy