| Kernel driver pkgtemp |
| ====================== |
| |
| Supported chips: |
| * Intel family |
| Prefix: 'pkgtemp' |
| CPUID: |
| Datasheet: Intel 64 and IA-32 Architectures Software Developer's Manual |
| Volume 3A: System Programming Guide |
| |
| Author: Fenghua Yu |
| |
| Description |
| ----------- |
| |
| This driver permits reading package level temperature sensor embedded inside |
| Intel CPU package. The sensors can be in core, uncore, memory controller, or |
| other components in a package. The feature is first implemented in Intel Sandy |
| Bridge platform. |
| |
| Temperature is measured in degrees Celsius and measurement resolution is |
| 1 degree C. Valid temperatures are from 0 to TjMax degrees C, because the actual |
| value of temperature register is in fact a delta from TjMax. |
| |
| Temperature known as TjMax is the maximum junction temperature of package. |
| We get this from MSR_IA32_TEMPERATURE_TARGET. If the MSR is not accessible, |
| we define TjMax as 100 degrees Celsius. At this temperature, protection |
| mechanism will perform actions to forcibly cool down the package. Alarm |
| may be raised, if the temperature grows enough (more than TjMax) to trigger |
| the Out-Of-Spec bit. Following table summarizes the exported sysfs files: |
| |
| temp1_input - Package temperature (in millidegrees Celsius). |
| temp1_max - All cooling devices should be turned on. |
| temp1_crit - Maximum junction temperature (in millidegrees Celsius). |
| temp1_crit_alarm - Set when Out-of-spec bit is set, never clears. |
| Correct CPU operation is no longer guaranteed. |
