Commit | Line | Data |
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d58ee056 RM |
1 | Kernel driver coretemp |
2 | ====================== | |
3 | ||
4 | Supported chips: | |
5 | * All Intel Core family | |
6 | Prefix: 'coretemp' | |
7 | CPUID: family 0x6, models 0xe, 0xf | |
8 | Datasheet: Intel 64 and IA-32 Architectures Software Developer's Manual | |
9 | Volume 3A: System Programming Guide | |
10 | ||
11 | Author: Rudolf Marek | |
12 | ||
13 | Description | |
14 | ----------- | |
15 | ||
16 | This driver permits reading temperature sensor embedded inside Intel Core CPU. | |
17 | Temperature is measured in degrees Celsius and measurement resolution is | |
18 | 1 degree C. Valid temperatures are from 0 to TjMax degrees C, because | |
19 | the actual value of temperature register is in fact a delta from TjMax. | |
20 | ||
21 | Temperature known as TjMax is the maximum junction temperature of processor. | |
22 | Intel defines this temperature as 85C or 100C. At this temperature, protection | |
23 | mechanism will perform actions to forcibly cool down the processor. Alarm | |
24 | may be raised, if the temperature grows enough (more than TjMax) to trigger | |
25 | the Out-Of-Spec bit. Following table summarizes the exported sysfs files: | |
26 | ||
27 | temp1_input - Core temperature (in millidegrees Celsius). | |
28 | temp1_crit - Maximum junction temperature (in millidegrees Celsius). | |
29 | temp1_crit_alarm - Set when Out-of-spec bit is set, never clears. | |
30 | Correct CPU operation is no longer guaranteed. | |
31 | temp1_label - Contains string "Core X", where X is processor | |
32 | number. | |
33 | ||
34 | The TjMax temperature is set to 85 degrees C if undocumented model specific | |
35 | register (UMSR) 0xee has bit 30 set. If not the TjMax is 100 degrees C as | |
36 | (sometimes) documented in processor datasheet. |