Disable bitsandbytes quantization for Qwen3.5-A3B/MoE models which don't support it

coderai

@@ -665,7 +665,13 @@ class NvidiaBackend(ModelBackend):
         # Prepare model loading arguments
         load_kwargs = {'trust_remote_code': True}
         
+        # Check if model supports quantization
         if load_in_4bit or load_in_8bit:
+            # Qwen3.5-A3B/MoE models don't support bitsandbytes quantization
+            if 'qwen3.5' in model_name.lower() and ('a3b' in model_name.lower() or 'moe' in model_name.lower()):
+                print(f"Warning: {model_name} does not support bitsandbytes quantization (load_in_4bit/load_in_8bit)")
+                print("Quantization disabled for this model")
+            else:
                 try:
                     import bitsandbytes as bnb
                     print(f"Using {4 if load_in_4bit else 8}-bit quantization")