Documentation/ABI/testing/sysfs-class-thermal

   1 What:           /sys/class/thermal/thermal_zoneX/type
   2 Description:
   3                 Strings which represent the thermal zone type.
   4                 This is given by thermal zone driver as part of registration.
   5                 E.g: "acpitz" indicates it's an ACPI thermal device.
   6                 In order to keep it consistent with hwmon sys attribute; this
   7                 should be a short, lowercase string, not containing spaces nor
   8                 dashes.
   9
  10                 RO, Required
  11
  12 What:           /sys/class/thermal/thermal_zoneX/temp
  13 Description:
  14                 Current temperature as reported by thermal zone (sensor).
  15
  16                 Unit: millidegree Celsius
  17
  18                 RO, Required
  19
  20 What:           /sys/class/thermal/thermal_zoneX/mode
  21 Description:
  22                 One of the predefined values in [enabled, disabled].
  23                 This file gives information about the algorithm that is
  24                 currently managing the thermal zone. It can be either default
  25                 kernel based algorithm or user space application.
  26
  27                 enabled
  28                                 enable Kernel Thermal management.
  29                 disabled
  30                                 Preventing kernel thermal zone driver actions upon
  31                                 trip points so that user application can take full
  32                                 charge of the thermal management.
  33
  34                 RW, Optional
  35
  36 What:           /sys/class/thermal/thermal_zoneX/policy
  37 Description:
  38                 One of the various thermal governors used for a particular zone.
  39
  40                 RW, Required
  41
  42 What:           /sys/class/thermal/thermal_zoneX/available_policies
  43 Description:
  44                 Available thermal governors which can be used for a
  45                 particular zone.
  46
  47                 RO, Required
  48
  49 What:           /sys/class/thermal/thermal_zoneX/trip_point_Y_temp
  50 Description:
  51                 The temperature above which trip point will be fired.
  52
  53                 Unit: millidegree Celsius
  54
  55                 RO, Optional
  56
  57 What:           /sys/class/thermal/thermal_zoneX/trip_point_Y_type
  58 Description:
  59                 Strings which indicate the type of the trip point.
  60
  61                 E.g. it can be one of critical, hot, passive, `active[0-*]`
  62                 for ACPI thermal zone.
  63
  64                 RO, Optional
  65
  66 What:           /sys/class/thermal/thermal_zoneX/trip_point_Y_hyst
  67 Description:
  68                 The hysteresis value for a trip point, represented as an
  69                 integer.
  70
  71                 Unit: Celsius
  72
  73                 RW, Optional
  74
  75 What:           /sys/class/thermal/thermal_zoneX/cdevY
  76 Description:
  77         Sysfs link to the thermal cooling device node where the sys I/F
  78         for cooling device throttling control represents.
  79
  80         RO, Optional
  81
  82 What:           /sys/class/thermal/thermal_zoneX/cdevY_trip_point
  83 Description:
  84                 The trip point in this thermal zone which `cdev[0-*]` is
  85                 associated with; -1 means the cooling device is not
  86                 associated with any trip point.
  87
  88                 RO, Optional
  89
  90 What:           /sys/class/thermal/thermal_zoneX/cdevY_weight
  91 Description:
  92                 The influence of `cdev[0-*]` in this thermal zone. This value
  93                 is relative to the rest of cooling devices in the thermal
  94                 zone. For example, if a cooling device has a weight double
  95                 than that of other, it's twice as effective in cooling the
  96                 thermal zone.
  97
  98                 RW, Optional
  99
 100 What:           /sys/class/thermal/thermal_zoneX/emul_temp
 101 Description:
 102                 Interface to set the emulated temperature method in thermal zone
 103                 (sensor). After setting this temperature, the thermal zone may
 104                 pass this temperature to platform emulation function if
 105                 registered or cache it locally. This is useful in debugging
 106                 different temperature threshold and its associated cooling
 107                 action. This is write only node and writing 0 on this node
 108                 should disable emulation.
 109
 110                 Unit: millidegree Celsius
 111
 112                 WO, Optional
 113
 114                 WARNING:
 115                     Be careful while enabling this option on production systems,
 116                     because userland can easily disable the thermal policy by simply
 117                     flooding this sysfs node with low temperature values.
 118
 119
 120 What:           /sys/class/thermal/thermal_zoneX/k_d
 121 Description:
 122                 The derivative term of the power allocator governor's PID
 123                 controller. For more information see
 124                 Documentation/driver-api/thermal/power_allocator.rst
 125
 126                 RW, Optional
 127
 128 What:           /sys/class/thermal/thermal_zoneX/k_i
 129 Description:
 130                 The integral term of the power allocator governor's PID
 131                 controller. This term allows the PID controller to compensate
 132                 for long term drift. For more information see
 133                 Documentation/driver-api/thermal/power_allocator.rst
 134
 135                 RW, Optional
 136
 137 What:           /sys/class/thermal/thermal_zoneX/k_po
 138 Description:
 139                 The proportional term of the power allocator governor's PID
 140                 controller during temperature overshoot. Temperature overshoot
 141                 is when the current temperature is above the "desired
 142                 temperature" trip point. For more information see
 143                 Documentation/driver-api/thermal/power_allocator.rst
 144
 145                 RW, Optional
 146
 147 What:           /sys/class/thermal/thermal_zoneX/k_pu
 148 Description:
 149                 The proportional term of the power allocator governor's PID
 150                 controller during temperature undershoot. Temperature undershoot
 151                 is when the current temperature is below the "desired
 152                 temperature" trip point. For more information see
 153                 Documentation/driver-api/thermal/power_allocator.rst
 154
 155                 RW, Optional
 156
 157 What:           /sys/class/thermal/thermal_zoneX/integral_cutoff
 158 Description:
 159                 Temperature offset from the desired temperature trip point
 160                 above which the integral term of the power allocator
 161                 governor's PID controller starts accumulating errors. For
 162                 example, if integral_cutoff is 0, then the integral term only
 163                 accumulates error when temperature is above the desired
 164                 temperature trip point. For more information see
 165                 Documentation/driver-api/thermal/power_allocator.rst
 166
 167                 Unit: millidegree Celsius
 168
 169                 RW, Optional
 170
 171 What:           /sys/class/thermal/thermal_zoneX/slope
 172 Description:
 173                 The slope constant used in a linear extrapolation model
 174                 to determine a hotspot temperature based off the sensor's
 175                 raw readings. It is up to the device driver to determine
 176                 the usage of these values.
 177
 178                 RW, Optional
 179
 180 What:           /sys/class/thermal/thermal_zoneX/offset
 181 Description:
 182                 The offset constant used in a linear extrapolation model
 183                 to determine a hotspot temperature based off the sensor's
 184                 raw readings. It is up to the device driver to determine
 185                 the usage of these values.
 186
 187                 RW, Optional
 188
 189 What:           /sys/class/thermal/thermal_zoneX/sustainable_power
 190 Description:
 191                 An estimate of the sustained power that can be dissipated by
 192                 the thermal zone. Used by the power allocator governor. For
 193                 more information see
 194                 Documentation/driver-api/thermal/power_allocator.rst
 195
 196                 Unit: milliwatts
 197
 198                 RW, Optional
 199
 200 What:           /sys/class/thermal/cooling_deviceX/type
 201 Description:
 202                 String which represents the type of device, e.g:
 203
 204                 - for generic ACPI: should be "Fan", "Processor" or "LCD"
 205                 - for memory controller device on intel_menlow platform:
 206                   should be "Memory controller".
 207
 208                 RO, Required
 209
 210 What:           /sys/class/thermal/cooling_deviceX/max_state
 211 Description:
 212                 The maximum permissible cooling state of this cooling device.
 213
 214                 RO, Required
 215
 216 What:           /sys/class/thermal/cooling_deviceX/cur_state
 217 Description:
 218                 The current cooling state of this cooling device.
 219                 The value can any integer numbers between 0 and max_state:
 220
 221                 - cur_state == 0 means no cooling
 222                 - cur_state == max_state means the maximum cooling.
 223
 224                 RW, Required
 225
 226 What:           /sys/class/thermal/cooling_deviceX/stats/reset
 227 Description:
 228                 Writing any value resets the cooling device's statistics.
 229
 230                 WO, Required
 231
 232 What:           /sys/class/thermal/cooling_deviceX/stats/time_in_state_ms:
 233 Description:
 234                 The amount of time spent by the cooling device in various
 235                 cooling states. The output will have "<state> <time>" pair
 236                 in each line, which will mean this cooling device spent <time>
 237                 msec of time at <state>.
 238
 239                 Output will have one line for each of the supported states.
 240
 241                 RO, Required
 242
 243 What:           /sys/class/thermal/cooling_deviceX/stats/total_trans
 244 Description:
 245                 A single positive value showing the total number of times
 246                 the state of a cooling device is changed.
 247
 248                 RO, Required
 249
 250 What:           /sys/class/thermal/cooling_deviceX/stats/trans_table
 251 Description:
 252                 This gives fine grained information about all the cooling state
 253                 transitions. The cat output here is a two dimensional matrix,
 254                 where an entry <i,j> (row i, column j) represents the number
 255                 of transitions from State_i to State_j. If the transition
 256                 table is bigger than PAGE_SIZE, reading this will return
 257                 an -EFBIG error.
 258
 259                 RO, Required