---
id: pr-flashinfer-2956
repo: flashinfer-ai/flashinfer
pr: 2956
title: '[Fmha] revert blackwell ultra optimization that causes deadlocks.'
author: PerkzZheng
date: '2026-04-03'
url: https://github.com/flashinfer-ai/flashinfer/pull/2956
source_category: upstream-code
architectures:
- sm100
tags: []
techniques: []
hardware_features: []
kernel_types: []
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: 5758837a8594c15aaae14e4e638fa4e634632c53
inclusion_reason: include
changed_paths:
- flashinfer/artifacts.py
- include/flashinfer/trtllm/fmha/kernelParams.h
artifact_dir: evidence/pull-bundles/flashinfer/gh-2956
head_ref_oid: 4885d5a129def333747477ae419544b5803120c6
---
# [Fmha] revert blackwell ultra optimization that causes deadlocks.

- Repository: `flashinfer-ai/flashinfer`
- PR: [2956](https://github.com/flashinfer-ai/flashinfer/pull/2956)
- Decision: `include`
- Reason: include

## Changed Paths

- `flashinfer/artifacts.py`
- `include/flashinfer/trtllm/fmha/kernelParams.h`

## Evidence Bundle

`evidence/pull-bundles/flashinfer/gh-2956`
