# Thermal core framework
The thermal core is part of the upstream Linux solution for thermal management. It
helps in monitoring and identifying instances of inadequate power supply so that the thermal
mitigation action can be applied.
The thermal core emergency frequency mitigation is handled by limits management hardware
(LMH).
The Qualcomm initiative is to make the limits management solution available using exclusively
upstreamed code. The following are the key functions of thermal core:
- Core isolation
- GPU junction temperature (Tj) management
- Skin temperature (Tskin) management (optional)
The figure shows the thermal core framework within the context of Qualcomm limits management
solution:
Figure : Thermal core framework architecture
- When user space governor is used in thermal\_zone, a notification is sent to the thermal
engine after the sensor is tripped.
- The mitigation actions are aggregated using the cooling devices.
- Of-thermal interface parses the device tree as well as aggregates thresholds and sends to
the sensor drivers.
For more information, see Thermal Core Overview (80-P9301-113).
The following is an example of an annotated thermal zone from the chipset dtsi file:
## Read mitigation level from Sysfs
The mitigation level is exposed through cooling\_device node in the sysfs filesystem, which
can be found at sys/class/thermal/cooling\_deviceX/cur\_state.
The `cooling_deviceX/cur_state`GPU mitigation level is exposed.
- “X” denotes the cooling\_device number that represents devfreq (node for GPU)
- cur\_state reflects the mitigation index and not the actual value.
- If there is no mitigation, cur\_state reads as 0.
- Values above 0 represent incrementally deeper mitigation.
Table : Cooling device mitigation level
| Mitigation level | Performance level |
| --- | --- |
| 0 | Full performance |
| 1 | Full perf - 1 |
| 2 | Full perf - 2 |
| 3 | Full perf - 3 |
| . . . | . . . |
| n | Minimum performance |
**Parent Topic:** [Software thermal management](https://docs.qualcomm.com/doc/80-88500-4/topic/52_Software_thermal_management.html)
Last Published: Aug 18, 2023
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