diff --git a/vllm/model_executor/models/whisper_causal.py b/vllm/model_executor/models/whisper_causal.py
index 8e4322ea335d..455d23080168 100644
--- a/vllm/model_executor/models/whisper_causal.py
+++ b/vllm/model_executor/models/whisper_causal.py
@@ -30,14 +30,6 @@
     CommonAttentionMetadata,
     subclass_attention_backend_with_overrides,
 )
-from vllm.v1.attention.backends.flash_attn import FlashAttentionBackend
-
-try:
-    from vllm.v1.attention.backends.rocm_aiter_fa import AiterFlashAttentionBackend
-except ImportError:
-    AiterFlashAttentionBackend = None
-from vllm.v1.attention.backends.rocm_attn import RocmAttentionBackend
-from vllm.v1.attention.backends.triton_attn import TritonAttentionBackend
 from vllm.v1.attention.selector import get_attn_backend
 from vllm.v1.kv_cache_interface import AttentionSpec
 
@@ -211,36 +203,6 @@ def forward(
                 output_block_scale,
             )
 
-    _SUPPORTED_BACKENDS = tuple(
-        b
-        for b in (
-            AiterFlashAttentionBackend,
-            FlashAttentionBackend,
-            RocmAttentionBackend,
-            TritonAttentionBackend,
-        )
-        if b is not None
-    )
-
-    if not issubclass(underlying_attn_backend, _SUPPORTED_BACKENDS):
-        raise NotImplementedError(
-            f"{underlying_attn_backend} is not yet supported."
-            "Contributions to support more backends are much "
-            "appreciated."
-        )
-
-    if not issubclass(underlying_attn_backend, FlashAttentionBackend):
-        logger.info(
-            "Using %s for Whisper causal attention with block pooling. "
-            "This backend was recently enabled for this model. "
-            "If you encounter any accuracy or performance issues, "
-            "please open an issue at "
-            "https://github.com/vllm-project/vllm/issues "
-            "with the [ROCm] tag so it can be triaged by the "
-            "appropriate team.",
-            underlying_attn_backend.get_name(),
-        )
-
     attn_backend = subclass_attention_backend_with_overrides(
         name_prefix=prefix,
         attention_backend_cls=underlying_attn_backend,
@@ -251,13 +213,14 @@ def forward(
             block_size,
             num_kv_heads,
             head_size,
-            cache_dtype_str: underlying_attn_backend.get_kv_cache_shape(
-                num_blocks,
-                # we stretch each block by `block_pool_size`
-                block_size * block_pool_size,
-                num_kv_heads // block_pool_size,
-                head_size,
-                cache_dtype_str,
+            cache_dtype_str: (
+                underlying_attn_backend.get_kv_cache_shape(
+                    num_blocks,
+                    block_size * block_pool_size,
+                    num_kv_heads // block_pool_size,
+                    head_size,
+                    cache_dtype_str,
+                )
             ),
             "forward_includes_kv_cache_update": True,
         },