[Bugfix][ROCm][DSv4.1] Disable SWA bounded replay on ROCm (#57906)

Signed-off-by: Fangzhou Ai <fangzhou.ai@amd.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

vllm/models/deepseek_v41/attention.py

@@ -531,6 +531,15 @@ class DeepseekV4Attention(nn.Module, AttentionLayerBase, ABC):
                 "instead."
             )
             swa_bounded_replay = False
+        if swa_bounded_replay and current_platform.is_rocm():
+            logger.warning_once(
+                "SWA bounded replay is off on ROCm (the sparse SWA metadata "
+                "builders forward replay_start, but the window clamp it relies "
+                "on lives in the FlashInfer and FlashMLA prefill kernels, so "
+                "the padded slots fault); the sliding-window cache takes part "
+                "in prefix caching instead."
+            )
+            swa_bounded_replay = False
         self.swa_cache_layer = DeepseekV4SWACache(
             head_dim=self.head_dim,
             window_size=self.window_size,