From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Date: Tue, 18 Nov 2008 12:33:37 +0000 Subject: Re: [lm-sensors] [PATCH 1/2] k8temp warn about errata Message-Id: <20081118133337.109020ce@hyperion.delvare> List-Id: References: <48E3F505.40401@assembler.cz> In-Reply-To: <48E3F505.40401@assembler.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lm-sensors@vger.kernel.org On Tue, 18 Nov 2008 12:18:45 +0100, Andreas Herrmann wrote: > On Tue, Nov 18, 2008 at 11:40:52AM +0100, Jean Delvare wrote: > > The whole point of hardware monitoring is to report accurate values. > > > > Additional software can be used to take actions based on temperature > > values, for example fan speed regulation or CPU frequency changes. If > > you can't trust the temperature readings then these operations become > > dangerous. > > Then we need to blacklist it. The suggested workaround for this erratum is > to use "temperature measurements from an analog thermal diode" for thermal > control ... > If the system should be designed not to rely on the thermal sensor > (due to accuracy issue) the OS shouldn't use it either. My point exactly. > > That being said, I guess that the example above is essentially > > theoretical? Most cases we've seen so far were not off by 5 degrees. > > They were plain wrong, with reported temperatures being in the -20 to > > +15 degrees C. > > Was this observed with k8temp or other sensor chips? k8temp. See my list of obviously incorrect values at: http://lists.lm-sensors.org/pipermail/lm-sensors/2008-October/024584.html After seeing these values, I admit I had a smile when seeing how AMD had formulated the errata (sensor doesn't meet a certain accuracy threshold...) -- Jean Delvare _______________________________________________ lm-sensors mailing list lm-sensors@lm-sensors.org http://lists.lm-sensors.org/mailman/listinfo/lm-sensors