---
id: pr-tensorrt-llm-13486
repo: NVIDIA/TensorRT-LLM
pr: 13486
title: '[None][fix] visual_gen UlyssesAttention: pass post-A2A seq_len to inner backend'
author: karljang
date: '2026-04-29'
url: https://github.com/NVIDIA/TensorRT-LLM/pull/13486
source_category: upstream-code
architectures:
- sm100
tags:
- attention kernel
- fmha
techniques: []
hardware_features: []
kernel_types:
- attention
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 3b7af1c21f1071d57ada08641f0f76c4827ae961
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- tensorrt_llm/_torch/visual_gen/attention_backend/parallel.py
artifact_dir: evidence/pull-bundles/tensorrt-llm/gh-13486
head_ref_oid: e885a5560e5c8e1669be06852a8e3eb18fa75bcf
---
# [None][fix] visual_gen UlyssesAttention: pass post-A2A seq_len to inner backend

- Repository: `NVIDIA/TensorRT-LLM`
- PR: [13486](https://github.com/NVIDIA/TensorRT-LLM/pull/13486)
- Decision: `Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.`
- Reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.

## Changed Paths

- `tensorrt_llm/_torch/visual_gen/attention_backend/parallel.py`

## Evidence Bundle

`evidence/pull-bundles/tensorrt-llm/gh-13486`
