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Rudolf Marekef4c4fd2006-09-24 20:50:57 +02001Kernel driver k8temp
2====================
3
4Supported chips:
Rudolf Marek4660cb32006-10-08 22:01:26 +02005 * AMD Athlon64/FX or Opteron CPUs
Rudolf Marekef4c4fd2006-09-24 20:50:57 +02006 Prefix: 'k8temp'
7 Addresses scanned: PCI space
8 Datasheet: http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/32559.pdf
9
10Author: Rudolf Marek
11Contact: Rudolf Marek <r.marek@sh.cvut.cz>
12
13Description
14-----------
15
Rudolf Marek4660cb32006-10-08 22:01:26 +020016This driver permits reading temperature sensor(s) embedded inside AMD K8
17family CPUs (Athlon64/FX, Opteron). Official documentation says that it works
18from revision F of K8 core, but in fact it seems to be implemented for all
19revisions of K8 except the first two revisions (SH-B0 and SH-B3).
20
21Please note that you will need at least lm-sensors 2.10.1 for proper userspace
22support.
Rudolf Marekef4c4fd2006-09-24 20:50:57 +020023
24There can be up to four temperature sensors inside single CPU. The driver
25will auto-detect the sensors and will display only temperatures from
26implemented sensors.
27
28Mapping of /sys files is as follows:
29
30temp1_input - temperature of Core 0 and "place" 0
31temp2_input - temperature of Core 0 and "place" 1
32temp3_input - temperature of Core 1 and "place" 0
33temp4_input - temperature of Core 1 and "place" 1
34
35Temperatures are measured in degrees Celsius and measurement resolution is
361 degree C. It is expected that future CPU will have better resolution. The
37temperature is updated once a second. Valid temperatures are from -49 to
38206 degrees C.
39
40Temperature known as TCaseMax was specified for processors up to revision E.
41This temperature is defined as temperature between heat-spreader and CPU
42case, so the internal CPU temperature supplied by this driver can be higher.
43There is no easy way how to measure the temperature which will correlate
44with TCaseMax temperature.
45
46For newer revisions of CPU (rev F, socket AM2) there is a mathematically
47computed temperature called TControl, which must be lower than TControlMax.
48
49The relationship is following:
50
51temp1_input - TjOffset*2 < TControlMax,
52
53TjOffset is not yet exported by the driver, TControlMax is usually
5470 degrees C. The rule of the thumb -> CPU temperature should not cross
5560 degrees C too much.