[Misc] Medusa supports custom bias (#10361)

Author: skylee-01

vllm/model_executor/models/medusa.py

@@ -14,11 +14,14 @@
 
 class ResidualBlock(nn.Module):
 
-    def __init__(self, hidden_size: int, num_layers: int) -> None:
+    def __init__(self, config: VllmConfig, hidden_size: int,
+                 num_layers: int) -> None:
         super().__init__()
 
         self.layers = nn.ModuleList([
-            nn.Linear(hidden_size, hidden_size, bias=False)
+            nn.Linear(hidden_size,
+                      hidden_size,
+                      bias=getattr(config, "medusa_fc_bias", False))
             for _ in range(num_layers)
         ])
         self.act = nn.SiLU()
@@ -49,7 +52,8 @@ def __init__(self, *, vllm_config: VllmConfig, prefix: str = "") -> None:
         super().__init__()
         self.config = config
         self.blocks = nn.ModuleList([
-            ResidualBlock(hidden_size=self.config.hidden_size,
+            ResidualBlock(config=config,
+                          hidden_size=self.config.hidden_size,
                           num_layers=self.config.num_hidden_layers)
             for _ in range(self.config.num_heads)
         ])