IPMItool returns false value on PowerEdge 1950

Harald_Jensas at Dell.com Harald_Jensas at Dell.com
Fri Dec 29 07:02:26 CST 2006


> To: linux-poweredge-Lists
> Subject: Re: IPMItool returns false value on PowerEdge 1950
> 

Have a look at page 86, 87 and 89 in this document.

http://www.intel.com/design/xeon/datashts/313355.htm 

There is no diode in the new processors to read an absolute CPU temperature from. The value you are seeing as negative is a releative value that the system use to control the fan's.

Quote:
"Fan speed control solutions utilize a TControl value stored in the processor
IA32_TEMPERATURE_TARGET MSR. Prior to Dual-Core Intel Xeon Processor 5100
Series, TControl represented a diode temperature. With Dual-Core Intel Xeon Processor
5100 Series, TControl represents an offset from TCC activation temperature.The DTS
outputs temperature offsets over the PECI interface in response to a GetTemp0()
command and these offsets are relative values vs. an absolute values."


Since GetTemp0() is used both on older CPUs with a diode, absolute values, and newer CPUs with digital thermal sensors, relative values, the BMC will add the sensor to the SDR list. And thus on systems with a newer CPU you will get the confusing relative readings.

I am not sure if this can be fixed, or if this can be fixed in BMC firmware or ipmitool...


Your hardware is working as expected. Just disregard the CPU temp values you are seeing.


--
Harald Jensås



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