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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-06 10:02:58 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-06 10:02:58 -0700 |
| commit | a5e11599da95fbe8425db0cfd01a581d7412d0c9 (patch) | |
| tree | 45fccb4b27a1068cec8dc8283260893b60ca46d2 /Documentation | |
| parent | 0f477dd0851bdcee82923da66a7fc4a44cb1bc3d (diff) | |
| parent | a3159864f2978bf2ace9cc787d73d315c98bbf9a (diff) | |
Merge branch 'x86-hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, hwmon: Package Level Thermal/Power: pkgtemp documentation
x86, hwmon: Package Level Thermal/Power: power limit
x86, hwmon: Package Level Thermal/Power: thermal throttling handler
x86, hwmon: Package Level Thermal/Power: pkgtemp hwmon driver
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/hwmon/pkgtemp | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/Documentation/hwmon/pkgtemp b/Documentation/hwmon/pkgtemp new file mode 100644 index 00000000000..c8e1fb0fadd --- /dev/null +++ b/Documentation/hwmon/pkgtemp @@ -0,0 +1,36 @@ +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. |