Fix compressor kv_score: use forward() for NVFP4 quantized weights

Raw torch.mm doesn't work with packed uint8 NVFP4 weights.
Use MergedColumnParallelLinear.forward() which handles dequantization.

vllm/patches/deepseek_v4_attention.py

@@ -366,9 +366,17 @@ class DeepseekV4MultiHeadLatentAttentionWrapper(PluggableLayer):
             compressor = self.compressor
 
             def compressor_kv_score() -> torch.Tensor:
+                # For NVFP4-quantized weights, we can't do a raw torch.mm
+                # with packed uint8 weights. Use the layer's forward()
+                # which handles dequantization properly.
+                wkv_wgate_weight = compressor.fused_wkv_wgate.weight
+                if wkv_wgate_weight.dtype == torch.uint8:
+                    # NVFP4 packed weights — use forward() for dequant+matmul
+                    score, _ = compressor.fused_wkv_wgate(hidden_states)
+                    return score.to(torch.float32)
                 return torch.mm(
                     hidden_states,
-                    compressor.fused_wkv_wgate.weight.T,
+                    wkv_wgate_weight.T,
                     out_dtype=torch.float32,
                 )
 
@@ -383,9 +391,13 @@ class DeepseekV4MultiHeadLatentAttentionWrapper(PluggableLayer):
                 return weights
 
             def indexer_compressor_kv_score() -> torch.Tensor:
+                wkv_wgate_weight = indexer.compressor.fused_wkv_wgate.weight
+                if wkv_wgate_weight.dtype == torch.uint8:
+                    score, _ = indexer.compressor.fused_wkv_wgate(hidden_states)
+                    return score.to(torch.float32)
                 return torch.mm(
                     hidden_states,
-                    indexer.compressor.fused_wkv_wgate.weight.T,
+                    wkv_wgate_weight.T,
                     out_dtype=torch.float32,
                 )