Cc: Rudolf Marek <r.marek@...>, Maxim Levitsky <maximlevitsky@...>, <trenn@...>, Len Brown <lenb@...>, Matthew <jackdachef@...>, <linux-acpi@...>, <torvalds@...>, <linux-kernel@...>, Zhang, Rui <rui.zhang@...>
On Wed, 30 Apr 2008 02:11:14 +0200, Kasper Sandberg wrote:
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.
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
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