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1 | Kernel driver k8temp | ||
2 | ==================== | ||
3 | |||
4 | Supported chips: | ||
5 | * AMD K8 CPU | ||
6 | 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 | |||
10 | Author: Rudolf Marek | ||
11 | Contact: Rudolf Marek <r.marek@sh.cvut.cz> | ||
12 | |||
13 | Description | ||
14 | ----------- | ||
15 | |||
16 | This driver permits reading temperature sensor(s) embedded inside AMD K8 CPUs. | ||
17 | Official documentation says that it works from revision F of K8 core, but | ||
18 | in fact it seems to be implemented for all revisions of K8 except the first | ||
19 | two revisions (SH-B0 and SH-B3). | ||
20 | |||
21 | There can be up to four temperature sensors inside single CPU. The driver | ||
22 | will auto-detect the sensors and will display only temperatures from | ||
23 | implemented sensors. | ||
24 | |||
25 | Mapping of /sys files is as follows: | ||
26 | |||
27 | temp1_input - temperature of Core 0 and "place" 0 | ||
28 | temp2_input - temperature of Core 0 and "place" 1 | ||
29 | temp3_input - temperature of Core 1 and "place" 0 | ||
30 | temp4_input - temperature of Core 1 and "place" 1 | ||
31 | |||
32 | Temperatures are measured in degrees Celsius and measurement resolution is | ||
33 | 1 degree C. It is expected that future CPU will have better resolution. The | ||
34 | temperature is updated once a second. Valid temperatures are from -49 to | ||
35 | 206 degrees C. | ||
36 | |||
37 | Temperature known as TCaseMax was specified for processors up to revision E. | ||
38 | This temperature is defined as temperature between heat-spreader and CPU | ||
39 | case, so the internal CPU temperature supplied by this driver can be higher. | ||
40 | There is no easy way how to measure the temperature which will correlate | ||
41 | with TCaseMax temperature. | ||
42 | |||
43 | For newer revisions of CPU (rev F, socket AM2) there is a mathematically | ||
44 | computed temperature called TControl, which must be lower than TControlMax. | ||
45 | |||
46 | The relationship is following: | ||
47 | |||
48 | temp1_input - TjOffset*2 < TControlMax, | ||
49 | |||
50 | TjOffset is not yet exported by the driver, TControlMax is usually | ||
51 | 70 degrees C. The rule of the thumb -> CPU temperature should not cross | ||
52 | 60 degrees C too much. | ||