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a3159864 FY |
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. |