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Commands

Jetson Power Model

  • sudo nvpmodel -q Displays the current active power mode. Allows you to check which performance profile is currently in use.
  • sudo nvpmodel -m0 Maximum Performance Mode (MAXN)

Info

Enables maximum performance mode, activating all CPU cores and full GPU capability. Recommended for compute-intensive workloads such as YOLO, SLAM, image processing, and autonomous control loops

  • sudo nvpmodel -m1 Low Power Mode (5W)

Warning

Runs the Jetson in Low Power Mode. Reduces energy consumption but significantly limits performance.

sudo nvpmodel -q   # Show current power mode
sudo nvpmodel -m0  # MAX mode
sudo nvpmodel -m1  # 5W mode

Jetson Temperature Monitoring

  • cat /sys/class/thermal/thermal_zone*/temp Displays raw temperature readings (in millidegrees Celsius) for all available thermal zones.
  • cat /sys/class/thermal/thermal_zone*/type Shows the sensor name associated with each thermal zone (e.g., CPU-therm, GPU-therm, Tboard-therm).
  • sudo tegrastats Real-time monitoring tool for temperature, CPU/GPU usage, memory, and power consumption.
  • watch -n1 'cat /sys/class/thermal/thermal_zone*/temp' Continuously displays updated temperature readings every second.

Info

Each Jetson thermal sensor is represented as a thermal zone.
Temperature values are reported in millidegrees Celsius (e.g., 45000 → 45°C).
Use these readings to diagnose thermal throttling, cooling efficiency, and system load behavior.

Usage Example

cat /sys/class/thermal/thermal_zone1/type
cat /sys/class/thermal/thermal_zone1/temp
sudo tegrastats        # real-time monitoring

Warning

High temperatures can cause thermal throttling, reducing CPU/GPU frequencies and impacting performance.
Ensure proper cooling for compute-intensive workloads or enclosed environments.

Kernel DebugFS (debugfs) Overview

  • The gpio file lists the current state of all GPIO lines in the system. It shows each line’s associated controller (gpiochip), direction (input/output), current value, and usage status. It is one of the most reliable diagnostic sources for verifying which physical pin corresponds to which GPIO line on Jetson platforms. 

    sudo cat /sys/kernel/debug/gpio

  • The tegra_pinctrl_reg file contains the current pinmux configuration and pin controller register values for all pins on the Jetson platform. It is a critical reference for determining whether each pin is configured as GPIO, I2C, SPI, or another function, and for verifying that hardware configuration has been correctly applied. 

    sudo cat /sys/kernel/debug/tegra_pinctrl_reg

Low-Level Register Access with devmem2

  • devmem2 allows direct access to physical memory from userspace and enables read/write operations on hardware registers. It is mainly used to quickly test memory-mapped I/O (MMIO) registers.

Warning

Writing incorrect values to the wrong physical address using devmem2 may hang the system, trigger unexpected resets, or cause hardware misbehavior. Use this tool only if you fully understand the register map and have the SoC/Jetson TRM at hand.

Example

First, you can inspect the tegra_pinctrl_reg contents to understand which register regions are used for a given pin/pad:

sudo cat /sys/kernel/debug/tegra_pinctrl_reg

This output shows the register addresses and values associated with the pinmux/pad configuration for each pin. From here, you can identify the register address or offset used for a specific pin. 

# Read current value
sudo devmem2 0x[address] w

# Set the address value
sudo devmem2 0x[address] w 0x1