Weird fan behaviour on a 2950

Tony van Lingen tony.vanlingen at
Mon Jun 11 22:26:26 CDT 2007


Dirkjan Bussink wrote:
> Tony van Lingen wrote:
>> DirkJan,
> <offtopic>
> Dutch or from recent Dutch heritage? Because my name is without the
> second capital and only people with some sort of Dutch background would
> probably type it this way ;).
> </offtopic>
Soot! Caught me out there... but I did make sure this time :)
>> I don't think its purely cosmetic. Raghavendra says:
> Well, the way I read it, they don't have absolute sensors anymore, but
> relative ones. I've looked at the current values and they are very
> reasonable (so the negative temperature shows a realistic temperature
> given the overheating point and the temperatures in the data center).
> Also if there is no CPU present in a socket, it shows a totally
> different value (always 50 as the temperature, tested on various
> machines), indicating it does read something from the CPU.
> I've also find no reason behind the fact that the bit is set. It could
> be only because it is confusing, or because the data actually doesn't
> make any sense (in which case it would be very coincidental that the
> temperatures actually look like reasonable values). 
Reading the info in Roger While's link, that would make perfect sense (

Roger While said:
> This may or may not be helpful -

Without the CPU there's nothing to read, so it will return some default 
value. Judging by the thread above, the 50 value (wich is an offset, not 
temperature) would mean "boiling hot" - a safe default.

With the CPU present it would read out the IA32_TEMPERATURE_TARGET MSR, 
but the value would not have any documented meaning. Thus the solution 
to hide this reading is perfectly reasonable and not solely cosmetic - 
it could indeed give the impression that your system is OK when it's in 
fact not. To make it meaningful apparently you need to know a value for 
the PROCHOT assertion, which cannot be read and is implementation 
dependent. The hardware can still use it (for throttling fans), so it 
still makes sense for the bit to be set.
(my interpretation)

Tony van Lingen
Systems Administrator and DBA


WARNING: This e-mail (including any attachments) has originated from a Queensland Government department and may contain information that is confidential, private, or covered by legal professional privilege, and may be protected by copyright.  

You may use this e-mail only if you are the person(s) it was intended to be sent to and if you use it in an authorised way.  No one is allowed to use, review, alter, transmit, disclose, distribute, print or copy this e-mail without appropriate authority.  If you have received this e-mail in error, please inform the sender immediately by phone or e-mail and delete this e-mail, including any copies, from your computer system network and destroy any hardcopies.

Unless otherwise stated, this e-mail represents the views of the sender and not the views of the Environmental Protection Agency.

Although this e-mail has been checked for the presence of computer viruses, the Environmental Protection Agency provides no warranty that all viruses have been detected and cleaned. Any use of this e-mail could harm your computer system.  It is your responsibility to ensure that this e-mail does not contain and is not affected by computer viruses, defects or interference by third parties or replication problems (including incompatibility with your computer system).

E-mails sent to and from the Environmental Protection Agency will be electronically stored, managed and may be audited, in accordance with the law and Queensland Government Information Standards (IS31, IS38, IS40, IS41 and IS42) to the extent they are consistent with the law.


More information about the Linux-PowerEdge mailing list