thermal_slope

Source code: thermal_slope.py

Determines how fast the processor heats/cools.

Description

The purpose of this test is to detect devices without thermal paste.

The user should prepare one device with thermal paste and another device without it, run the tests on both of them, and then select the threshold of max_slope.

Different CPUs on the same board or the same CPU on different boards may have different max_slope distribution so the user should set different thresholds for different (model, CPU).

Test Procedure

This is an automated test without user interaction.

Details

1. ‘cool_down’ stage: Runs the fan at <cool_down_fan_rpm> until it reaches <cool_down_temperature_c> (at least <cool_down_min_duration_secs> but at most <cool_down_max_duration_secs>). Fails if unable to cool down to <cool_down_max_temperature_c>.

2. ‘idle’ stage: Spins the fan to <target_fan_rpm> and waits <fan_spin_down_secs>.

3. ‘one_core’ stage: Runs one core at full speed for <duration_secs>.

4. Determines the thermal slope during this period. The thermal slope is defined as

   ΔT / ΔP / Δt

   where

   ΔT is the change in temperature between the idle and one_core stages. ΔP is the change in power usage between the idle and one_core stages. Δt is the amount of time the one_core stage was run

   If the thermal slope is not between min_slope and max_slope, the test fails.

Dependency

• Device API cros.factory.device.fan.

• Device API cros.factory.device.memory.

• Device API cros.factory.device.storage.

• Device API cros.factory.device.thermal.

Examples

To collect the slope of a setting:

{
  "pytest_name": "thermal_slope",
  "args": {
    "cool_down_fan_rpm": 9999,
    "cool_down_min_duration_secs": 100,
    "cool_down_max_duration_secs": 600,
    "cool_down_temperature_c": 81,
    "cool_down_max_temperature_c": 94,
    "target_fan_rpm": 5001,
    "fan_spin_down_secs": 10,
    "duration_secs": 60,
    "min_slope": null,
    "max_slope": null
  }
}

To fail the device with slope out of range:

{
  "pytest_name": "thermal_slope",
  "args": {
    "cool_down_fan_rpm": 9999,
    "cool_down_min_duration_secs": 100,
    "cool_down_max_duration_secs": 600,
    "cool_down_temperature_c": 81,
    "cool_down_max_temperature_c": 94,
    "target_fan_rpm": 5001,
    "fan_spin_down_secs": 10,
    "duration_secs": 60,
    "min_slope": 0.05,
    "max_slope": 0.20
  }
}

Test Arguments

Name	Type	Description
cool_down_fan_rpm	int, float, str	(optional; default: 10000) Fan RPM during cool_down, or the string “auto”.
cool_down_min_duration_secs	int, float	(optional; default: 10) Minimum duration of cool_down
cool_down_max_duration_secs	int, float	(optional; default: 60) Maximum duration of cool_down
cool_down_temperature_c	int, float	(optional; default: 50) Target temperature for cool_down
cool_down_max_temperature_c	int, float, None	(optional; default: None) Maximum allowable temperature after cool_down (if higher than this, the test will not run). Defaults to cool_down_temperature_c
target_fan_rpm	int, float, str	(optional; default: 4000) Target RPM of fan during slope test, or the string “auto”.
fan_spin_down_secs	int, float	(optional; default: 5) Number of seconds to allow for fan spin down
duration_secs	int, float	(optional; default: 5) Duration of slope test
min_slope	int, float, None	(optional; default: None) Minimum allowable thermal slope in °C/J
max_slope	int, float, None	(optional; default: None) Maximum allowable thermal slope in °C/J
console_log	bool	(optional; default: False) Enable console log (disabling may make results more accurate since updating the console log on screen requires CPU cycles)
sensor_id	str, None	(optional; default: None) An id to specify the power sensor. See Thermal.GetPowerUsage.