[tip:x86/hwmon] x86, hwmon: Package Level Thermal/Power: pkgtemp documentation
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From: tip-bot for Fenghua Yu on 3 Aug 2010 20:10 Commit-ID: a3159864f2978bf2ace9cc787d73d315c98bbf9a Gitweb: http://git.kernel.org/tip/a3159864f2978bf2ace9cc787d73d315c98bbf9a Author: Fenghua Yu <fenghua.yu(a)intel.com> AuthorDate: Thu, 29 Jul 2010 17:13:46 -0700 Committer: H. Peter Anvin <hpa(a)linux.intel.com> CommitDate: Tue, 3 Aug 2010 15:58:56 -0700 x86, hwmon: Package Level Thermal/Power: pkgtemp documentation Document for package level thermal hwmon driver. Signed-off-by: Fenghua Yu <fenghua.yu(a)intel.com> LKML-Reference: <1280448826-12004-6-git-send-email-fenghua.yu(a)intel.com> Reviewed-by: Len Brown <len.brown(a)intel.com> Signed-off-by: H. Peter Anvin <hpa(a)linux.intel.com> --- 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 0000000..c8e1fb0 --- /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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |