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Update the documentation for the k8temp driver. Signed-off-by: Rudolf Marek <r.marek@assembler.cz> Signed-off-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
56 lines
2.0 KiB
Plaintext
56 lines
2.0 KiB
Plaintext
Kernel driver k8temp
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====================
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Supported chips:
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* AMD Athlon64/FX or Opteron CPUs
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Prefix: 'k8temp'
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Addresses scanned: PCI space
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Datasheet: http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/32559.pdf
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Author: Rudolf Marek
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Contact: Rudolf Marek <r.marek@sh.cvut.cz>
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Description
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-----------
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This driver permits reading temperature sensor(s) embedded inside AMD K8
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family CPUs (Athlon64/FX, Opteron). Official documentation says that it works
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from revision F of K8 core, but in fact it seems to be implemented for all
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revisions of K8 except the first two revisions (SH-B0 and SH-B3).
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Please note that you will need at least lm-sensors 2.10.1 for proper userspace
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support.
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There can be up to four temperature sensors inside single CPU. The driver
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will auto-detect the sensors and will display only temperatures from
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implemented sensors.
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Mapping of /sys files is as follows:
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temp1_input - temperature of Core 0 and "place" 0
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temp2_input - temperature of Core 0 and "place" 1
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temp3_input - temperature of Core 1 and "place" 0
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temp4_input - temperature of Core 1 and "place" 1
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Temperatures are measured in degrees Celsius and measurement resolution is
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1 degree C. It is expected that future CPU will have better resolution. The
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temperature is updated once a second. Valid temperatures are from -49 to
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206 degrees C.
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Temperature known as TCaseMax was specified for processors up to revision E.
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This temperature is defined as temperature between heat-spreader and CPU
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case, so the internal CPU temperature supplied by this driver can be higher.
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There is no easy way how to measure the temperature which will correlate
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with TCaseMax temperature.
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For newer revisions of CPU (rev F, socket AM2) there is a mathematically
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computed temperature called TControl, which must be lower than TControlMax.
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The relationship is following:
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temp1_input - TjOffset*2 < TControlMax,
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TjOffset is not yet exported by the driver, TControlMax is usually
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70 degrees C. The rule of the thumb -> CPU temperature should not cross
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60 degrees C too much.
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