[Bugfix] Guard mm_token_type_ids kwarg in get_mrope_input_positions (#35711)

Signed-off-by: Andreas Karatzas <akaratza@amd.com>

vllm/model_executor/models/transformers/multimodal.py

@@ -474,7 +474,19 @@ class MultiModalMixin(SupportsMultiModal, SupportsMRoPE):
         # can't accept arbitrary args, even if its value is `None`
         kwargs = {}
         if mm_token_type_ids:
-            kwargs["mm_token_type_ids"] = torch.cat(mm_token_type_ids)
+            if not hasattr(self, "_get_rope_index_accepts_mm_token_type_ids"):
+                import inspect
+
+                sig = inspect.signature(self.model.get_rope_index)
+                params = sig.parameters
+                self._get_rope_index_accepts_mm_token_type_ids = (
+                    "mm_token_type_ids" in params
+                    or any(
+                        p.kind == inspect.Parameter.VAR_KEYWORD for p in params.values()
+                    )
+                )
+            if self._get_rope_index_accepts_mm_token_type_ids:
+                kwargs["mm_token_type_ids"] = torch.cat(mm_token_type_ids)
 
         mrope_positions, mrope_position_delta = self.model.get_rope_index(
             input_ids=torch.tensor(input_tokens).unsqueeze(0),