| Fenghua Yu | a315986 | 2010-07-29 17:13:46 -0700 | [diff] [blame] | 1 | Kernel driver pkgtemp |
| 2 | ====================== |
| 3 | |
| 4 | Supported chips: |
| 5 | * Intel family |
| 6 | Prefix: 'pkgtemp' |
| 7 | CPUID: |
| 8 | Datasheet: Intel 64 and IA-32 Architectures Software Developer's Manual |
| 9 | Volume 3A: System Programming Guide |
| 10 | |
| 11 | Author: Fenghua Yu |
| 12 | |
| 13 | Description |
| 14 | ----------- |
| 15 | |
| 16 | This driver permits reading package level temperature sensor embedded inside |
| 17 | Intel CPU package. The sensors can be in core, uncore, memory controller, or |
| 18 | other components in a package. The feature is first implemented in Intel Sandy |
| 19 | Bridge platform. |
| 20 | |
| 21 | Temperature is measured in degrees Celsius and measurement resolution is |
| 22 | 1 degree C. Valid temperatures are from 0 to TjMax degrees C, because the actual |
| 23 | value of temperature register is in fact a delta from TjMax. |
| 24 | |
| 25 | Temperature known as TjMax is the maximum junction temperature of package. |
| 26 | We get this from MSR_IA32_TEMPERATURE_TARGET. If the MSR is not accessible, |
| 27 | we define TjMax as 100 degrees Celsius. At this temperature, protection |
| 28 | mechanism will perform actions to forcibly cool down the package. Alarm |
| 29 | may be raised, if the temperature grows enough (more than TjMax) to trigger |
| 30 | the Out-Of-Spec bit. Following table summarizes the exported sysfs files: |
| 31 | |
| 32 | temp1_input - Package temperature (in millidegrees Celsius). |
| 33 | temp1_max - All cooling devices should be turned on. |
| 34 | temp1_crit - Maximum junction temperature (in millidegrees Celsius). |
| 35 | temp1_crit_alarm - Set when Out-of-spec bit is set, never clears. |
| 36 | Correct CPU operation is no longer guaranteed. |