Sage Attention doesn't support head_dim >= 256

[theqmann]

Custom Node Testing

• [ ] I have tried disabling custom nodes and the issue persists (see how to disable custom nodes if you need help)

Expected Behavior

Comfy should not attempt to run sageattn() for cases where head_dim is one of the unsupported values. Should just bypass the call with some other attention. See https://github.com/thu-ml/SageAttention/issues/47

Actual Behavior

Comfy spits out continuous error messages with "Unsupported head dim"

Steps to Reproduce

Run a model (Pony7 in my case) with sage attention with an unsupported head_dim.

Debug Logs

[2025-11-09 10:39:33.383] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.384] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.384] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.385] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.386] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.388] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.389] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.389] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.390] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.391] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.392] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.393] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.394] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.394] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.395] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.396] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.396] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.
[2025-11-09 10:39:33.397] Error running sage attention: Unsupported head_dim: 256, using pytorch attention instead.

Other

No response