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Documentation / hwmon / pkgtemp


Based on kernel version 2.6.39.1. Page generated on 2011-06-03 13:46 EST.

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.
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