[OpenPower-Firmware] P8 overtemp behavior

[Sergey Kachkin]

Hi Daniel,


thanks a lot for your reply, but AFAIK we do not power off completely in
case of checkstop i.e there is still risk of damage. Am I wrong?

regards,
Sergey

On Thu, May 31, 2018 at 1:36 AM, Daniel M Crowell <dcrowell at us.ibm.com>
wrote:

> From one of our power/thermal management folks -
> HTMGT/OCC does not power off due to CPU overtemp it was always stated that
> the system would checkstop due to thermal runaway before causing damage.
> We would rather let it checkstop in that real case vs. shutting systems
> down due to a bad DTS reading.  The BMC can decide to do a shutdown based
> on the CPU temperatures that they get from the OCC, I know in P9 the
> OpenBMC did add this I don't recall if AMI BMC did this in P8.
>
> --
> Dan Crowell
> Senior Software Engineer - Power Systems Enablement Firmware
> IBM Rochester
> dcrowell at us.ibm.com
>
>
>
> From:        Sergey Kachkin <s.kachkin at gmail.com>
> To:        openpower-firmware at lists.ozlabs.org
> Date:        05/25/2018 07:54 AM
> Subject:        [OpenPower-Firmware] P8 overtemp behavior
> Sent by:        "OpenPower-Firmware" <openpower-firmware-bounces+dcrowell=
> us.ibm.com at lists.ozlabs.org>
> ------------------------------
>
>
>
> Hi Team,
>
> I've got a question regarding a P8 overtemp behavior.    After processors
> reach 85C (OPEN_POWER_PROC_DVFS_TEMP_DEG_C) OCC start frequency
> throttling.
>  I'm trying to figure out what would happen if temperature continues to
> grow? (broken fan/ condition).
>
> POWER8 User manual says: "Automated hardware thermal overtemperature
> protection is not supported. The real-time OCC firmware accomplishes this
> function."
>
> Is there any emergency power off mechanism due to overtemp on P8?
>
> thanks,
>
> regards,
> Sergey _______________________________________________
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>
>
>
>
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