TYAN TS75-B7122 Service Engineer's Manual page 166

5.3.11.6.2 Hardware PM State Control
Hardware P-State Control
Disable: Hardware chooses a P-state based on OS Request (Legacy P-States).
Native Mode: Hardware chooses a P-state based on OS guidance.
Out of Band Mode: Hardware autonomously chooses a P-state (no OS guidance).
Disabled / Native Mode / Out of Band Mode / Native Mode with No Legacy
Support
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