summaryrefslogtreecommitdiffstats
path: root/Documentation/hwmon/k8temp.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/hwmon/k8temp.rst')
-rw-r--r--Documentation/hwmon/k8temp.rst62
1 files changed, 62 insertions, 0 deletions
diff --git a/Documentation/hwmon/k8temp.rst b/Documentation/hwmon/k8temp.rst
new file mode 100644
index 000000000..ab25a73e7
--- /dev/null
+++ b/Documentation/hwmon/k8temp.rst
@@ -0,0 +1,62 @@
+Kernel driver k8temp
+====================
+
+Supported chips:
+
+ * AMD Athlon64/FX or Opteron CPUs
+
+ Prefix: 'k8temp'
+
+ Addresses scanned: PCI space
+
+ Datasheet: https://www.amd.com/system/files/TechDocs/32559.pdf
+
+Author: Rudolf Marek
+
+Contact: Rudolf Marek <r.marek@assembler.cz>
+
+Description
+-----------
+
+This driver permits reading temperature sensor(s) embedded inside AMD K8
+family CPUs (Athlon64/FX, Opteron). Official documentation says that it works
+from revision F of K8 core, but in fact it seems to be implemented for all
+revisions of K8 except the first two revisions (SH-B0 and SH-B3).
+
+Please note that you will need at least lm-sensors 2.10.1 for proper userspace
+support.
+
+There can be up to four temperature sensors inside single CPU. The driver
+will auto-detect the sensors and will display only temperatures from
+implemented sensors.
+
+Mapping of /sys files is as follows:
+
+============= ===================================
+temp1_input temperature of Core 0 and "place" 0
+temp2_input temperature of Core 0 and "place" 1
+temp3_input temperature of Core 1 and "place" 0
+temp4_input temperature of Core 1 and "place" 1
+============= ===================================
+
+Temperatures are measured in degrees Celsius and measurement resolution is
+1 degree C. It is expected that future CPU will have better resolution. The
+temperature is updated once a second. Valid temperatures are from -49 to
+206 degrees C.
+
+Temperature known as TCaseMax was specified for processors up to revision E.
+This temperature is defined as temperature between heat-spreader and CPU
+case, so the internal CPU temperature supplied by this driver can be higher.
+There is no easy way how to measure the temperature which will correlate
+with TCaseMax temperature.
+
+For newer revisions of CPU (rev F, socket AM2) there is a mathematically
+computed temperature called TControl, which must be lower than TControlMax.
+
+The relationship is following:
+
+ temp1_input - TjOffset*2 < TControlMax,
+
+TjOffset is not yet exported by the driver, TControlMax is usually
+70 degrees C. The rule of the thumb -> CPU temperature should not cross
+60 degrees C too much.