# Getting started
Source: [https://docs.qualcomm.com/doc/80-70014-30/topic/get-started-thermal.html](https://docs.qualcomm.com/doc/80-70014-30/topic/get-started-thermal.html)
The information here describes how to start developing your software on the Qualcomm
Linux platform. Ensure to set up the infrastructure before building your software. For more
information on setting up infrastructure, see [Qualcomm Linux Build Guide](https://docs.qualcomm.com/bundle/publicresource/topics/80-70014-254/introduction.html). This guide also
provides information about the common build workflows.
## Thermal mitigation policies
You must enable SSH in Permissive mode to securely access your host device. For
instructions, see [How to SSH?](https://docs.qualcomm.com/bundle/publicresource/topics/80-70014-254/how_to.html#how-to-ssh-).
Table : SoC temperature management techniques and description
| SoC temperature management techniques | Description |
| --- | --- |
| Software throttling | Software throttling is a mechanism where the Tsens hardware triggers an interrupt whenever the temperature in the system crosses the configured temperature threshold.
Following are the mitigation actions that the thermal framework initiates on the CPU in response to these interrupts:
Thermal DCVS
Reduces the maximum operating frequency if temperature thresholds are crossed
Voltage scaling occurs according to clock scaling, which reduces power consumption and in turn reduces temperature
CPU idle injection
Core is put in the deepest Low-Power state for configured idle time
|
| Hardware throttling | The SoC employs in-built hardware to execute thermal mitigation actions swiftly, ensuring system reliability.
Hardware throttling reduces the CPU clock speed to recover quickly from high thermal conditions. Following are the hardware throttling scenarios:
High thermal conditions (typically above 105°C of junction temperature)
Voltage drop at PMIC
Over current protection of battery
|
| SoC software shutdown | The SoC software shutdown is triggered when the temperature of any of the on-die Tsens reaches 118 °C. Upon receiving an interruption from Tsens, the thermal framework initiates graceful shutdown. |
| SoC hardware shutdown | The SoC hardware shutdown is triggered when the temperature of any of the on-die sensors reaches 120°C. |
The thermal mitigation policies regulate the thermal behavior of the platform.
The thermal framework operates in the following ways:
1. The thermal framework uses on-die temperature sensors (Tsens) to monitor
system's thermal response.
2. It applies mitigation based on thermal threshold limits as per the device
tree.
3. It provides software throttling, hardware throttling, SoC software shutdown,
and SoC hardware shutdown mitigation policies to control temperature.
Note: The thermal mitigation techniques are for information
purpose only. They help to understand performance regressions during high
thermal conditions.
To mitigate thermal conditions you can create your own thermal zone rules based on a
PCB thermistor. For more information, see [Configure a new thermal zone](https://docs.qualcomm.com/doc/80-70014-30/topic/customize.html#customize__section_lq4_xxb_51c).
**Parent Topic:** [Thermal management](https://docs.qualcomm.com/doc/80-70014-30/topic/thermalmanagement.html)
Last Published: Jul 15, 2024
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