[GH-ISSUE #4] It appears that backend CUDA is not enabled. Is this normal? #1

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opened 2026-10-26 22:18:59 +00:00 by bsakaguchi · 4 comments

bsakaguchi commented

2026-10-26 22:18:59 +00:00

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Originally created by @kevin98761234 on GitHub (Jan 6, 2026).
Original GitHub issue: https://github.com/Comfy-Org/comfy-kitchen/issues/4

comfyui e14f3b661069971163ddc56036b0f486933b9162
** Platform: Windows
** Python version: 3.12.11 (main, Jul 23 2025, 00:32:20) [MSC v.1944 64 bit (AMD64)]
pytorch version: 2.9.1+cu130
Device: cuda:0 NVIDIA GeForce RTX 5060 Ti : cudaMallocAsync

I installed the following from pip:
https://files.pythonhosted.org/packages/b8/54/996bcf5745065d5fecdb7c8597c086eb51987e51cce20cb291ef954a824b/comfy_kitchen-0.2.0-cp312-abi3-win_amd64.whl

Found comfy_kitchen backend eager: {'available': True, 'disabled': False, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8', 'scaled_mm_nvfp4']}

Found comfy_kitchen backend cuda: {'available': False, 'disabled': False, 'unavailable_reason': "cannot import name '_C' from partially initialized module 'comfy_kitchen.backends.cuda' (most likely due to a circular import) (C:\StabilityMatrix\Data\Packages\ComfyUI_cp312\venv\Lib\site-packages\comfy_kitchen\backends\cuda\init.py)", 'capabilities': []}

Found comfy_kitchen backend triton: {'available': True, 'disabled': True, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8']}

Originally created by @kevin98761234 on GitHub (Jan 6, 2026). Original GitHub issue: https://github.com/Comfy-Org/comfy-kitchen/issues/4 comfyui e14f3b661069971163ddc56036b0f486933b9162 ** Platform: Windows ** Python version: 3.12.11 (main, Jul 23 2025, 00:32:20) [MSC v.1944 64 bit (AMD64)] pytorch version: 2.9.1+cu130 Device: cuda:0 NVIDIA GeForce RTX 5060 Ti : cudaMallocAsync I installed the following from pip: https://files.pythonhosted.org/packages/b8/54/996bcf5745065d5fecdb7c8597c086eb51987e51cce20cb291ef954a824b/comfy_kitchen-0.2.0-cp312-abi3-win_amd64.whl Found comfy_kitchen backend eager: {'available': True, 'disabled': False, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8', 'scaled_mm_nvfp4']} Found comfy_kitchen backend cuda: {'available': False, 'disabled': False, 'unavailable_reason': "cannot import name '_C' from partially initialized module 'comfy_kitchen.backends.cuda' (most likely due to a circular import) (C:\\StabilityMatrix\\Data\\Packages\\ComfyUI_cp312\\venv\\Lib\\site-packages\\comfy_kitchen\\backends\\cuda\\__init__.py)", 'capabilities': []} Found comfy_kitchen backend triton: {'available': True, 'disabled': True, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8']}

bsakaguchi closed this issue

2026-10-26 22:18:59 +00:00

bsakaguchi commented

2026-10-26 22:19:00 +00:00

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@twri commented on GitHub (Jan 6, 2026):

python -c "import importlib.machinery as m; print(m.EXTENSION_SUFFIXES)"
['.cp312-win_amd64.pyd', '.pyd']

Making a copy of backends\cuda\_C.abi3.pyd to backends\cuda\_C.pyd solves issue.

d5b0c8723

if(WIN32)
  set_target_properties(_C PROPERTIES SUFFIX ".abi3.pyd")
endif()

@twri commented on GitHub (Jan 6, 2026): ``` python -c "import importlib.machinery as m; print(m.EXTENSION_SUFFIXES)" ['.cp312-win_amd64.pyd', '.pyd'] ``` Making a copy of `backends\cuda\_C.abi3.pyd` to `backends\cuda\_C.pyd` solves issue. [d5b0c8723](https://github.com/Comfy-Org/comfy-kitchen/commit/d5b0c872375153b0dcf8374c9537752afc783e6a) ``` if(WIN32) set_target_properties(_C PROPERTIES SUFFIX ".abi3.pyd") endif() ```

bsakaguchi commented

2026-10-26 22:19:00 +00:00

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@kevin98761234 commented on GitHub (Jan 6, 2026):

Thank you. Renaming it seems to have enabled CUDA. Flux.2 dev nvfp4 also worked without any issues!

@kevin98761234 commented on GitHub (Jan 6, 2026): Thank you. Renaming it seems to have enabled CUDA. Flux.2 dev nvfp4 also worked without any issues!

bsakaguchi commented

2026-10-26 22:19:00 +00:00

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@jovan2009 commented on GitHub (Jan 6, 2026):

python -c "import importlib.machinery as m; print(m.EXTENSION_SUFFIXES)"
['.cp312-win_amd64.pyd', '.pyd']
Making a copy of backends\cuda\_C.abi3.pyd to backends\cuda\_C.pyd solves issue.

d5b0c8723
if(WIN32)
  set_target_properties(_C PROPERTIES SUFFIX ".abi3.pyd")
endif()

I did copy _C.abi3.pyd to _C.pyd but for me it only changes the error, doesn't enable cuda:

Found comfy_kitchen backend triton: {'available': True, 'disabled': True, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8']}
Found comfy_kitchen backend cuda: {'available': False, 'disabled': False, 'unavailable_reason': 'DLL load failed while importing _C: The specified module could not be found.', 'capabilities': []}
Found comfy_kitchen backend eager: {'available': True, 'disabled': False, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8', 'scaled_mm_nvfp4']}

@jovan2009 commented on GitHub (Jan 6, 2026): > ``` > python -c "import importlib.machinery as m; print(m.EXTENSION_SUFFIXES)" > ['.cp312-win_amd64.pyd', '.pyd'] > ``` > > Making a copy of `backends\cuda\_C.abi3.pyd` to `backends\cuda\_C.pyd` solves issue. > > [d5b0c8723](https://github.com/Comfy-Org/comfy-kitchen/commit/d5b0c872375153b0dcf8374c9537752afc783e6a) > > ``` > if(WIN32) > set_target_properties(_C PROPERTIES SUFFIX ".abi3.pyd") > endif() > ``` I did copy _C.abi3.pyd to _C.pyd but for me it only changes the error, doesn't enable cuda: ``` Found comfy_kitchen backend triton: {'available': True, 'disabled': True, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8']} Found comfy_kitchen backend cuda: {'available': False, 'disabled': False, 'unavailable_reason': 'DLL load failed while importing _C: The specified module could not be found.', 'capabilities': []} Found comfy_kitchen backend eager: {'available': True, 'disabled': False, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8', 'scaled_mm_nvfp4']} ```

bsakaguchi commented

2026-10-26 22:19:01 +00:00

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@x5nder commented on GitHub (Jan 7, 2026):

Same issue here:
Found comfy_kitchen backend cuda: {'available': False, 'disabled': False, 'unavailable_reason': 'DLL load failed while importing _C: The specified module could not be found.', 'capabilities': []}

@x5nder commented on GitHub (Jan 7, 2026): Same issue here: `Found comfy_kitchen backend cuda: {'available': False, 'disabled': False, 'unavailable_reason': 'DLL load failed while importing _C: The specified module could not be found.', 'capabilities': []}`

bsakaguchi referenced this issue

2026-10-26 22:20:08 +00:00

[PR #1] [MERGED] Refactors to quantization code, fixes to README + LICENSE #76

bsakaguchi referenced this issue

2026-10-26 22:21:23 +00:00

[PR #166] [CLOSED] Merge test #190