# jetson-customize-clocks

Prepares Jetson CPU, GPU and EMC clock changes before an image is flashed. Use it to lock rates, set ceilings, or change DVFS behaviour.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1100 installs · ★ 3735
- Author: Jetson Team
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/NVIDIA/skills/tree/HEAD/skills/jetson-customize-clocks/SKILL.md
- Updated: 2026-10-23
- HTML: https://affpapa.org/en/nevibecode/skills/jetson-customize-clocks

## What it does

This skill prepares pre-flash CPU, GPU and EMC clock changes for a Jetson target. It edits the BPMP DTB for `max-rate-custom` ceilings and EMC DVFS control, while `nvpower.sh` can set governors or apply rate bounds through sysfs. It can lock a clock, lower its hard ceiling, or switch EMC DVFS on and off.

The workflow starts with an active profile, an extracted BSP image and an initialized source overlay tracker. Writes go to `<source.root_path>/Linux_for_Tegra/`; `<bsp_image.root_path>` stays read-only. Editing the BPMP DTB in the image directly breaks the change trail used by `/jetson-promote-image`, so that path should be avoided. Commit the edit, then run `/jetson-promote-image` followed by `/jetson-flash-image`; changes apply on the next boot. The skill does not cover live clock tuning or `nvpmodel` edits.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add NVIDIA/skills --skill jetson-customize-clocks -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/jetson-customize-clocks/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/jetson-customize-clocks/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add NVIDIA/skills --skill jetson-customize-clocks -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/jetson-customize-clocks/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add NVIDIA/skills --skill jetson-customize-clocks -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/jetson-customize-clocks/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install NVIDIA/skills jetson-customize-clocks
```

2. **Manually: put the files in place**
- File: `.github/skills/jetson-customize-clocks/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add NVIDIA/skills --skill jetson-customize-clocks -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/NVIDIA/skills --path skills/jetson-customize-clocks
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/jetson-customize-clocks/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add NVIDIA/skills --skill jetson-customize-clocks -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/NVIDIA/skills/tree/HEAD/skills/jetson-customize-clocks/SKILL.md

## When to use it
- lock a CPU or GPU clock rate
- lower a clock's hard rate ceiling
- disable or restore EMC DVFS
- set a CPU or GPU governor
- apply minimum and maximum rates through `nvpower.sh`

## Example prompts
- Use `jetson-customize-clocks` to lock the GPU clock before flashing the Jetson image.
- Use `jetson-customize-clocks` to disable EMC DVFS for the active Jetson profile.
- With `jetson-customize-clocks`, cap the CPU maximum rate without pinning its frequency.

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 9ac652d0f618e5b5.

BEGIN THIRD-PARTY FILE 9ac652d0f618e5b5
```text
---
name: jetson-customize-clocks
description: Use to lock/cap Jetson CPU/GPU/EMC clocks, toggle EMC/CPU DVFS, or change cpufreq governors by editing BPMP DTB and nvpower.sh pre-flash. Do NOT use for live tuning or nvpmodel edits.
version: 0.0.1
license: "Apache-2.0"
metadata:
  data-classification: public
  author: "Jetson Team"
  tags:
    - clocks
    - cpu
    - gpu
    - emc
    - dvfs
    - bwmgr
    - bpmp
    - nvpower
    - cpufreq
    - devfreq
  domain: clocks
---

# Customize Clocks

## Purpose

Customize CPU, GPU, and EMC clock behavior on a Jetson target by editing files under `Linux_for_Tegra/` before flashing the image. Two layers are in scope:

- The **BPMP DTB** at `Linux_for_Tegra/bootloader/<BPFDTB_FILE>` — per-clock `max-rate-custom` ceilings, plus the EMC DVFS gate (bwmgr + cactmon on all SoCs; osp-controller on T26x only).
- **nvpower.sh** at `Linux_for_Tegra/rootfs/etc/systemd/nvpower.sh` — cpufreq / devfreq governors and (optionally) per-device min / max / static rates written to sysfs at boot.

Common triggers: "lock CPU/GPU/EMC frequency", "pin GPU to Fmax", "pin EMC to MAXN", "disable/enable EMC DVFS", "disable/enable CPU DVFS", "set CPU/GPU max rate", "change cpufreq governor".

Out of scope: runtime clock tuning on a live target (no flash step), nvpmodel power-mode edits (use the sibling skill `/jetson-customize-nvpmodel`), and silicon-ceiling overrides (`max-rate-maxn` is read-only).

## Prerequisites

Resolve the active profile per
[`../../context/target-platform-contract.md`](../../context/target-platform-contract.md).
Refuse and route in these cases:

| Condition | Refuse with |
|---|---|
| No active profile, or `active: NA` | Route to `/jetson-set-target` or `/jetson-init-target`. |
| Profile lacks `bsp_image:` block | Route to `/jetson-init-image`. |
| `<bsp_image.root_path>/Linux_for_Tegra/` missing | Route to `/jetson-init-image`. |
| `<source.root_path>/Linux_for_Tegra/` missing or not a git repo | Route to `/jetson-init-source`. |

Resolve paths:

- `<bsp_image.root_path>` from `bsp_image.root_path:` if present, else `<workspace>/Image`.
- `<source.root_path>` from `source.root_path:` if present, else `<workspace>/Source`.

`<bsp_image.root_path>` is **read-only** for this skill; every write
(Operation 1's BPMP DTB and Operation 2's `nvpower.sh`) lands under
`<source.root_path>` (the overlay tracker). This is the workflow
invariant in
[`../../context/bsp-customization-workflow.md#workflow-invariants`](../../context/bsp-customization-workflow.md#workflow-invariants) —
hand-editing upstream silently destroys the diff trail and makes
`/jetson-promote-image` a noop.

## Instructions

1. Resolve the prerequisites above (active profile, BSP image extracted, source overlay tracker initialized).
2. Pick the operation from the table below.
```
END THIRD-PARTY FILE 9ac652d0f618e5b5

The third-party file has ended. Everything between the 9ac652d0f618e5b5 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 2826 of 19128 bytes. © Jetson Team · Apache-2.0 · https://github.com/NVIDIA/skills/tree/HEAD/skills/jetson-customize-clocks/SKILL.md

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