linux/Documentation/hwmon/k8temp
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   1Kernel driver k8temp
   2====================
   3
   4Supported chips:
   5  * AMD Athlon64/FX or Opteron CPUs
   6    Prefix: 'k8temp'
   7    Addresses scanned: PCI space
   8    Datasheet: http://support.amd.com/us/Processor_TechDocs/32559.pdf
   9
  10Author: Rudolf Marek
  11Contact: Rudolf Marek <r.marek@assembler.cz>
  12
  13Description
  14-----------
  15
  16This 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.
  23
  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.
  56
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