[V1] [Bugfix] eagle bugfix and enable correct lm_head for multimodal (2) (vllm-project#18781)

Signed-off-by: Ronald Xu <ronaldxu@amazon.com>
Signed-off-by: amit <amit.man@gmail.com>

Author: RonaldBXu

vllm/transformers_utils/configs/eagle.py

@@ -70,7 +70,7 @@ def __init__(self,
 
         if self.model is not None:
             for k, v in self.model.to_dict().items():
-                if not hasattr(self, k):
+                if k not in kwargs:
                     setattr(self, k, v)
 
     @classmethod

vllm/v1/spec_decode/eagle.py

@@ -9,6 +9,7 @@
 from vllm.forward_context import set_forward_context
 from vllm.logger import init_logger
 from vllm.model_executor.model_loader import get_model
+from vllm.model_executor.models import supports_multimodal
 from vllm.model_executor.models.llama_eagle3 import Eagle3LlamaForCausalLM
 from vllm.v1.attention.backends.flash_attn import (CommonAttentionMetadata,
                                                    FlashAttentionMetadata)
@@ -346,7 +347,10 @@ def load_model(self, target_model: nn.Module) -> None:
         if self.vllm_config.speculative_config.method != "eagle3" and \
                 hasattr(target_model, "lm_head"):
             logger.info("Loading EAGLE LM head weights from the target model.")
-            self.model.lm_head = target_model.lm_head
+            if supports_multimodal(target_model):
+                self.model.lm_head = target_model.get_language_model().lm_head
+            else:
+                self.model.lm_head = target_model.lm_head
 
     @torch.inference_mode()
     def dummy_run(