### What this PR does / why we need it
This PR fixes a startup regression for Ascend hybrid attention + mamba
models after upgrading to vLLM `0.18.0`.
However, after the vLLM `0.18.0` upgrade, worker initialization still
calls the generic platform hook:
- `current_platform.update_block_size_for_backend(vllm_config)`
### How this PR fixes it
This PR keeps the fix strictly inside `vllm-ascend`.
It adds an Ascend override for
`NPUPlatform.update_block_size_for_backend()`:
- for hybrid models, do not run the generic upstream block-size fallback
- preserve the block size that was already computed by the hybrid
model-specific config logic
- for non-hybrid models, keep the original upstream behavior unchanged
- vLLM version: v0.18.0
- vLLM main:
8b6325758c
---------
Signed-off-by: maoxx241 <maomaoyu870@gmail.com>
Signed-off-by: Mengqing Cao <cmq0113@163.com>
Co-authored-by: Mengqing Cao <cmq0113@163.com>
9d0b7c8e98