{"record":{"id":"bd0d31a73e76bfd0","repo":"vllm-project/vllm","slug":"unknown-mamba-ssu-backend-name-valid-options","errorCode":null,"errorMessage":"Unknown Mamba SSU backend: '{name}'. Valid options are: {valid}","messagePattern":"Unknown Mamba SSU backend: '(.+?)'\\. Valid options are: (.+?)","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"vllm/config/mamba.py","lineNumber":20,"sourceCode":"# SPDX-FileCopyrightText: Copyright contributors to the vLLM project\n\nfrom enum import Enum, EnumMeta\nfrom typing import Any, Literal, get_args\n\nfrom pydantic import field_validator\n\nfrom vllm.config.utils import config\n\n\nclass _MambaBackendEnumMeta(EnumMeta):\n    \"\"\"Metaclass for MambaBackendEnum to provide better error messages.\"\"\"\n\n    def __getitem__(cls, name: str):\n        try:\n            return super().__getitem__(name)\n        except KeyError:\n            valid = \", \".join(cls.__members__.keys())\n            raise ValueError(\n                f\"Unknown Mamba SSU backend: '{name}'. Valid options are: {valid}\"\n            ) from None\n\n\nclass MambaBackendEnum(Enum, metaclass=_MambaBackendEnumMeta):\n    \"\"\"Enumeration of supported Mamba SSU (selective state update) backends.\"\"\"\n\n    TRITON = \"triton\"\n    FLASHINFER = \"flashinfer\"\n    CPU = \"cpu\"\n\n\nMambaSSUAlgorithm = Literal[\"auto\", \"simple\", \"vertical\", \"horizontal\"]\n\n\n@config\nclass MambaConfig:\n    \"\"\"Configuration for Mamba SSM backends.\"\"\"","sourceCodeStart":2,"sourceCodeEnd":38,"githubUrl":"https://github.com/vllm-project/vllm/blob/c794754062d49a8fdb63ab3c5215b488b865030c/vllm/config/mamba.py#L2-L38","documentation":"Error \"Unknown Mamba SSU backend: '{name}'. Valid options are: {valid}\" thrown in vllm-project/vllm.","triggerScenarios":"Raised at vllm/config/mamba.py:20 when validation fails: Unknown Mamba SSU backend. Typically triggered by an incompatible or incomplete vLLM configuration, an unsupported platform/backend combination, or a runtime resource/dependency that is missing.","commonSituations":"Commonly encountered at vllm/config/mamba.py:20 during vLLM startup/config validation or runtime setup when: (1) conflicting CLI flags or config fields are combined, (2) the current platform (CUDA/ROCm/CPU/XPU) or installed optional packages do not support the requested feature, or (3) a required value is absent or out of range. Resolve by correcting the configuration as described in the message, or by selecting a supported alternative.","solutions":["Choose one of the valid Mamba SSU backends listed in the error for --mamba-backend."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"c794754062d49a8fdb63ab3c5215b488b865030c","analyzedAt":"2026-08-14T21:17:39.825Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}