Blackwell Xid 149: NETIR Subcodes and Link Evidence
Interpret Blackwell Xid 149 using NETIR subcodes, fatality, peer evidence and topology. Separate link recovery from an unsupported GPU replacement verdict.
Preserve the complete Xid 149 NETIR message, payload and fatality, not just the number. NVIDIA assigns different actions to link-down, BER and MFDE variants. Peer failures can produce local reports; Xid 149 does not identify a defective GPU by itself.
- Root cause
- The full variant and local/peer evidence determine whether to investigate software, signal integrity, cables or another device.
- Recommended fix
- Preserve a vendor diagnostic bundle before approved recovery clears state.
- How Denpex helps
- Denpex investigates Blackwell Xid 149: NETIR Subcodes and Link Evidence using the evidence you provide or your connected workload collects. Earlier rank, host or application evidence is needed to distinguish an initiating failure from a downstream report.
What this failure is
Generation-specific NVLink event interpretation based on the complete NETIR variant and affected link endpoints.
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Why it happens (the mechanism)
The catalog distinguishes link events, bit-error-rate events and other NETIR conditions. A reporting endpoint can be downstream of a peer fault, so a clean local workload traceback is not enough to locate the initiator.
What you'll observe
- A collective or transfer stops progressing while NETIR events appear.
Common symptoms and what they mean
Check possible explanations against the incident evidence. A matching symptom alone does not establish its cause.
| Symptom | Possible explanation |
|---|---|
| Xid 149 with NETIR_LINK_EVT/NETIR_LINK_DOWN, NETIR_BER_EVENT or NETIR_MFDE_EVENT | The full variant and local/peer evidence determine whether to investigate software, signal integrity, cables or another device. |
Which systems are affected
- Blackwell platforms whose installed driver and vendor catalog report the Xid 149 NETIR family
How to confirm this is the problem
Use this checklist to test the hypothesis against a small reproduction. No single line proves the root cause, so preserve the preceding events and compare one variable at a time.
- ✓Capture full NETIR names, payloads, fatality, link/port identity and nearby Xid 154 action.
- ✓Map local and remote endpoints using the actual rack topology. Compare their event order without assuming clocks are synchronized.
- ✓Compare fabric membership and counter changes with expected state. An inactive link can be expected on some topologies.
Root cause
- The full variant and local/peer evidence determine whether to investigate software, signal integrity, cables or another device.
The fix and how to prevent it
The fix and the prevention pattern
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Why the recommended fix works
Variant and peer-aware triage narrows the failing path without equating every link report with a broken local board.
Diagnose this failure in VS Code
Select the traceback or open the failed terminal, then run Denpex locally to inspect matched failure patterns, supporting evidence and next checks without uploading the log. Verify recommendations against your workload before changing production.
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Frequently asked questions
Questions engineers and on-call staff commonly ask about this failure.
Does every Xid 149 require the same action?
Don't just read the fix, diagnose your run
The encyclopedia explains documented failure patterns. Denpex investigates your logs, configuration and stack, shows the supporting evidence, and asks for missing details when needed.