On Wed, 30 Apr 2008 02:11:14 +0200, Kasper Sandberg wrote: > On Wed, 2008-04-30 at 00:14 +0200, Rudolf Marek wrote: > > Well again, I tried hard at Intel and I really could not get any info on some > > calibration bit. The temperature is non-physical on arbitrary scale. I changed > > that so for some people it jumped to 100C, for some it remained. > > So, im confused.. The reason for this is that the internal sensor is > operating on some sort of weird scale, and thus when you interpolate it > into "your" scale, it doesent quite come out in the actual degrees > celcius the cpu temperature really is? It's really only an offset, rather than scaling. The temperature reported by the Core and Core2 CPUs is a relative temperature. It tells how far you are from the maximum temperature the CPU can survive. The value is expressed in (relative) degrees C. Rudolf did his best to find out the (absolute) temperature each CPU model can survive (known as TJmax) so that the coretemp driver can provide an absolute temperature to user-space, as all other hardware monitoring drivers do. Our hope was to limit the confusion, but it seems we failed ;) Maybe it would be better if the driver was reporting the relative temperature value directly when we don't know the TJmax value for sure - but then all user-space tools would need to learn how to deal with this. > so if i understand this correctly, the coretemp output does NOT > represent the actual deg celcius temperature my cpu is? It should, but there's no guarantee on desktop/server CPUs. It can be offset by 15°C if the driver's heuristic to determine TJmax for your CPU is incorrect. I guess the offset could even be different - after all the documentation we got from Intel was incomplete so we don't really know. -- Jean Delvare -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
