diff options
Diffstat (limited to 'kernel/Documentation/thermal/sysfs-api.txt')
| -rw-r--r-- | kernel/Documentation/thermal/sysfs-api.txt | 105 |
1 files changed, 100 insertions, 5 deletions
diff --git a/kernel/Documentation/thermal/sysfs-api.txt b/kernel/Documentation/thermal/sysfs-api.txt index 87519cb37..10f062ea6 100644 --- a/kernel/Documentation/thermal/sysfs-api.txt +++ b/kernel/Documentation/thermal/sysfs-api.txt @@ -95,7 +95,7 @@ temperature) and throttle appropriate devices. 1.3 interface for binding a thermal zone device with a thermal cooling device 1.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz, int trip, struct thermal_cooling_device *cdev, - unsigned long upper, unsigned long lower); + unsigned long upper, unsigned long lower, unsigned int weight); This interface function bind a thermal cooling device to the certain trip point of a thermal zone device. @@ -110,6 +110,8 @@ temperature) and throttle appropriate devices. lower:the Minimum cooling state can be used for this trip point. THERMAL_NO_LIMIT means no lower limit, and the cooling device can be in cooling state 0. + weight: the influence of this cooling device in this thermal + zone. See 1.4.1 below for more information. 1.3.2 int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz, int trip, struct thermal_cooling_device *cdev); @@ -127,9 +129,15 @@ temperature) and throttle appropriate devices. This structure defines the following parameters that are used to bind a zone with a cooling device for a particular trip point. .cdev: The cooling device pointer - .weight: The 'influence' of a particular cooling device on this zone. - This is on a percentage scale. The sum of all these weights - (for a particular zone) cannot exceed 100. + .weight: The 'influence' of a particular cooling device on this + zone. This is relative to the rest of the cooling + devices. For example, if all cooling devices have a + weight of 1, then they all contribute the same. You can + use percentages if you want, but it's not mandatory. A + weight of 0 means that this cooling device doesn't + contribute to the cooling of this zone unless all cooling + devices have a weight of 0. If all weights are 0, then + they all contribute the same. .trip_mask:This is a bit mask that gives the binding relation between this thermal zone and cdev, for a particular trip point. If nth bit is set, then the cdev and thermal zone are bound @@ -172,10 +180,19 @@ Thermal zone device sys I/F, created once it's registered: |---temp: Current temperature |---mode: Working mode of the thermal zone |---policy: Thermal governor used for this zone + |---available_policies: Available thermal governors for this zone |---trip_point_[0-*]_temp: Trip point temperature |---trip_point_[0-*]_type: Trip point type |---trip_point_[0-*]_hyst: Hysteresis value for this trip point |---emul_temp: Emulated temperature set node + |---sustainable_power: Sustainable dissipatable power + |---k_po: Proportional term during temperature overshoot + |---k_pu: Proportional term during temperature undershoot + |---k_i: PID's integral term in the power allocator gov + |---k_d: PID's derivative term in the power allocator + |---integral_cutoff: Offset above which errors are accumulated + |---slope: Slope constant applied as linear extrapolation + |---offset: Offset constant applied as linear extrapolation Thermal cooling device sys I/F, created once it's registered: /sys/class/thermal/cooling_device[0-*]: @@ -192,6 +209,8 @@ thermal_zone_bind_cooling_device/thermal_zone_unbind_cooling_device. /sys/class/thermal/thermal_zone[0-*]: |---cdev[0-*]: [0-*]th cooling device in current thermal zone |---cdev[0-*]_trip_point: Trip point that cdev[0-*] is associated with + |---cdev[0-*]_weight: Influence of the cooling device in + this thermal zone Besides the thermal zone device sysfs I/F and cooling device sysfs I/F, the generic thermal driver also creates a hwmon sysfs I/F for each _type_ @@ -238,6 +257,10 @@ policy One of the various thermal governors used for a particular zone. RW, Required +available_policies + Available thermal governors which can be used for a particular zone. + RO, Required + trip_point_[0-*]_temp The temperature above which trip point will be fired. Unit: millidegree Celsius @@ -265,6 +288,14 @@ cdev[0-*]_trip_point point. RO, Optional +cdev[0-*]_weight + The influence of cdev[0-*] in this thermal zone. This value + is relative to the rest of cooling devices in the thermal + zone. For example, if a cooling device has a weight double + than that of other, it's twice as effective in cooling the + thermal zone. + RW, Optional + passive Attribute is only present for zones in which the passive cooling policy is not supported by native thermal driver. Default is zero @@ -289,6 +320,66 @@ emul_temp because userland can easily disable the thermal policy by simply flooding this sysfs node with low temperature values. +sustainable_power + An estimate of the sustained power that can be dissipated by + the thermal zone. Used by the power allocator governor. For + more information see Documentation/thermal/power_allocator.txt + Unit: milliwatts + RW, Optional + +k_po + The proportional term of the power allocator governor's PID + controller during temperature overshoot. Temperature overshoot + is when the current temperature is above the "desired + temperature" trip point. For more information see + Documentation/thermal/power_allocator.txt + RW, Optional + +k_pu + The proportional term of the power allocator governor's PID + controller during temperature undershoot. Temperature undershoot + is when the current temperature is below the "desired + temperature" trip point. For more information see + Documentation/thermal/power_allocator.txt + RW, Optional + +k_i + The integral term of the power allocator governor's PID + controller. This term allows the PID controller to compensate + for long term drift. For more information see + Documentation/thermal/power_allocator.txt + RW, Optional + +k_d + The derivative term of the power allocator governor's PID + controller. For more information see + Documentation/thermal/power_allocator.txt + RW, Optional + +integral_cutoff + Temperature offset from the desired temperature trip point + above which the integral term of the power allocator + governor's PID controller starts accumulating errors. For + example, if integral_cutoff is 0, then the integral term only + accumulates error when temperature is above the desired + temperature trip point. For more information see + Documentation/thermal/power_allocator.txt + RW, Optional + +slope + The slope constant used in a linear extrapolation model + to determine a hotspot temperature based off the sensor's + raw readings. It is up to the device driver to determine + the usage of these values. + RW, Optional + +offset + The offset constant used in a linear extrapolation model + to determine a hotspot temperature based off the sensor's + raw readings. It is up to the device driver to determine + the usage of these values. + RW, Optional + ***************************** * Cooling device attributes * ***************************** @@ -318,7 +409,8 @@ passive, active. If an ACPI thermal zone supports critical, passive, active[0] and active[1] at the same time, it may register itself as a thermal_zone_device (thermal_zone1) with 4 trip points in all. It has one processor and one fan, which are both registered as -thermal_cooling_device. +thermal_cooling_device. Both are considered to have the same +effectiveness in cooling the thermal zone. If the processor is listed in _PSL method, and the fan is listed in _AL0 method, the sys I/F structure will be built like this: @@ -330,6 +422,7 @@ method, the sys I/F structure will be built like this: |---temp: 37000 |---mode: enabled |---policy: step_wise + |---available_policies: step_wise fair_share |---trip_point_0_temp: 100000 |---trip_point_0_type: critical |---trip_point_1_temp: 80000 @@ -340,8 +433,10 @@ method, the sys I/F structure will be built like this: |---trip_point_3_type: active1 |---cdev0: --->/sys/class/thermal/cooling_device0 |---cdev0_trip_point: 1 /* cdev0 can be used for passive */ + |---cdev0_weight: 1024 |---cdev1: --->/sys/class/thermal/cooling_device3 |---cdev1_trip_point: 2 /* cdev1 can be used for active[0]*/ + |---cdev1_weight: 1024 |cooling_device0: |---type: Processor |