xref: /OK3568_Linux_fs/kernel/Documentation/hwmon/k8temp.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593SmuzhiyunKernel driver k8temp
2*4882a593Smuzhiyun====================
3*4882a593Smuzhiyun
4*4882a593SmuzhiyunSupported chips:
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun  * AMD Athlon64/FX or Opteron CPUs
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun    Prefix: 'k8temp'
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun    Addresses scanned: PCI space
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun    Datasheet: https://www.amd.com/system/files/TechDocs/32559.pdf
13*4882a593Smuzhiyun
14*4882a593SmuzhiyunAuthor: Rudolf Marek
15*4882a593Smuzhiyun
16*4882a593SmuzhiyunContact: Rudolf Marek <r.marek@assembler.cz>
17*4882a593Smuzhiyun
18*4882a593SmuzhiyunDescription
19*4882a593Smuzhiyun-----------
20*4882a593Smuzhiyun
21*4882a593SmuzhiyunThis driver permits reading temperature sensor(s) embedded inside AMD K8
22*4882a593Smuzhiyunfamily CPUs (Athlon64/FX, Opteron). Official documentation says that it works
23*4882a593Smuzhiyunfrom revision F of K8 core, but in fact it seems to be implemented for all
24*4882a593Smuzhiyunrevisions of K8 except the first two revisions (SH-B0 and SH-B3).
25*4882a593Smuzhiyun
26*4882a593SmuzhiyunPlease note that you will need at least lm-sensors 2.10.1 for proper userspace
27*4882a593Smuzhiyunsupport.
28*4882a593Smuzhiyun
29*4882a593SmuzhiyunThere can be up to four temperature sensors inside single CPU. The driver
30*4882a593Smuzhiyunwill auto-detect the sensors and will display only temperatures from
31*4882a593Smuzhiyunimplemented sensors.
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33*4882a593SmuzhiyunMapping of /sys files is as follows:
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35*4882a593Smuzhiyun============= ===================================
36*4882a593Smuzhiyuntemp1_input   temperature of Core 0 and "place" 0
37*4882a593Smuzhiyuntemp2_input   temperature of Core 0 and "place" 1
38*4882a593Smuzhiyuntemp3_input   temperature of Core 1 and "place" 0
39*4882a593Smuzhiyuntemp4_input   temperature of Core 1 and "place" 1
40*4882a593Smuzhiyun============= ===================================
41*4882a593Smuzhiyun
42*4882a593SmuzhiyunTemperatures are measured in degrees Celsius and measurement resolution is
43*4882a593Smuzhiyun1 degree C. It is expected that future CPU will have better resolution. The
44*4882a593Smuzhiyuntemperature is updated once a second. Valid temperatures are from -49 to
45*4882a593Smuzhiyun206 degrees C.
46*4882a593Smuzhiyun
47*4882a593SmuzhiyunTemperature known as TCaseMax was specified for processors up to revision E.
48*4882a593SmuzhiyunThis temperature is defined as temperature between heat-spreader and CPU
49*4882a593Smuzhiyuncase, so the internal CPU temperature supplied by this driver can be higher.
50*4882a593SmuzhiyunThere is no easy way how to measure the temperature which will correlate
51*4882a593Smuzhiyunwith TCaseMax temperature.
52*4882a593Smuzhiyun
53*4882a593SmuzhiyunFor newer revisions of CPU (rev F, socket AM2) there is a mathematically
54*4882a593Smuzhiyuncomputed temperature called TControl, which must be lower than TControlMax.
55*4882a593Smuzhiyun
56*4882a593SmuzhiyunThe relationship is following:
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun	temp1_input - TjOffset*2 < TControlMax,
59*4882a593Smuzhiyun
60*4882a593SmuzhiyunTjOffset is not yet exported by the driver, TControlMax is usually
61*4882a593Smuzhiyun70 degrees C. The rule of the thumb -> CPU temperature should not cross
62*4882a593Smuzhiyun60 degrees C too much.
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