| Kernel driver k8temp |
| ==================== |
| |
| Supported chips: |
| * AMD Athlon64/FX or Opteron CPUs |
| Prefix: 'k8temp' |
| Addresses scanned: PCI space |
| Datasheet: http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/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. |