a3159864f2
Document for package level thermal hwmon driver. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> LKML-Reference: <1280448826-12004-6-git-send-email-fenghua.yu@intel.com> Reviewed-by: Len Brown <len.brown@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
37 lines
1.5 KiB
Plaintext
37 lines
1.5 KiB
Plaintext
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.
|