Re: Linux 2.6.25 (coretemp reads high temperatures)

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To: Kasper Sandberg <lkml@...>
Cc: Rudolf Marek <r.marek@...>, Maxim Levitsky <maximlevitsky@...>, <trenn@...>, Len Brown <lenb@...>, Matthew <jackdachef@...>, <linux-acpi@...>, <torvalds@...>, <linux-kernel@...>, Zhang, Rui <rui.zhang@...>
Date: Wednesday, April 30, 2008 - 2:20 am

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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Messages in current thread:
Linux 2.6.25, Matthew, (Fri Apr 18, 11:37 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Len Brown, (Fri Apr 18, 9:51 pm)
Re: Linux 2.6.25 (coretemp reads high temperatures), Maxim Levitsky, (Wed Apr 23, 4:43 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Kasper Sandberg, (Mon Apr 28, 2:19 pm)
Re: Linux 2.6.25 (coretemp reads high temperatures), Thomas Renninger, (Tue Apr 29, 9:07 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Jean Delvare, (Tue Apr 29, 11:08 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Rudolf Marek, (Tue Apr 29, 6:14 pm)
Re: Linux 2.6.25 (coretemp reads high temperatures), Pavel Machek, (Fri May 2, 4:35 pm)
Re: Linux 2.6.25 (coretemp reads high temperatures), Kasper Sandberg, (Tue Apr 29, 8:11 pm)
Re: Linux 2.6.25 (coretemp reads high temperatures), Jean Delvare, (Wed Apr 30, 2:20 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Henrique de Moraes Holschuh..., (Wed Apr 30, 10:51 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Pavel Machek, (Fri May 2, 4:36 pm)
Re: Linux 2.6.25 (coretemp reads high temperatures), Henrique de Moraes Holschuh..., (Sun May 4, 1:42 pm)
Re: Linux 2.6.25 (coretemp reads high temperatures), Pavel Machek, (Mon May 5, 9:45 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Jean Delvare, (Wed Apr 30, 11:28 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Jean Delvare, (Wed Apr 30, 2:10 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Henrique de Moraes Holschuh..., (Wed Apr 30, 10:46 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Pavel Machek, (Fri May 2, 4:35 pm)
Re: Linux 2.6.25 (coretemp reads high temperatures), Rudolf Marek, (Wed Apr 30, 10:50 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Jean Delvare, (Wed Apr 30, 11:18 am)
Re: Linux 2.6.25 (coretemp reads high temperatures), Thomas Bächler, (Mon Apr 21, 12:10 pm)
Re: Linux 2.6.25, Bart Van Assche, (Fri Apr 18, 3:18 pm)
Re: Linux 2.6.25, Jiri Slaby, (Fri Apr 18, 4:24 pm)
Re: Linux 2.6.25, Rudolf Marek, (Fri Apr 18, 4:50 pm)
Re: Linux 2.6.25, Gene Heskett, (Fri Apr 18, 12:27 pm)
Re: Linux 2.6.25, Gene Heskett, (Fri Apr 18, 12:24 pm)
Re: Linux 2.6.25, Linus Torvalds, (Fri Apr 18, 11:43 am)
Re: Linux 2.6.25, Cyrill Gorcunov, (Fri Apr 18, 3:38 pm)
Re: Linux 2.6.25, Cyrill Gorcunov, (Fri Apr 18, 4:03 pm)
Re: Linux 2.6.25, Rene Herman, (Fri Apr 18, 11:05 pm)
Re: Linux 2.6.25, Rene Herman, (Fri Apr 18, 11:20 pm)
Re: Linux 2.6.25, Cyrill Gorcunov, (Sat Apr 19, 2:17 am)
Re: Linux 2.6.25, Matthew, (Sat Apr 19, 6:18 am)
Re: Linux 2.6.25, Matthew, (Sat Apr 19, 6:22 am)
Re: Linux 2.6.25, Matthew, (Sun Apr 20, 8:02 am)
Re: Linux 2.6.25, Len Brown, (Wed Apr 23, 11:36 pm)
Re: Linux 2.6.25, Matthew, (Fri Apr 18, 12:02 pm)