[Bugfix][Qwen4Exp] Load PLE tables unquantized under Quark checkpoints (#59443)

Signed-off-by: Mikko Tukiainen <Mikko.Tukiainen@amd.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: TJian <tunjian.tan@embeddedllm.com>

tests/models/qwen4_exp/test_ple.py

@@ -26,6 +26,7 @@ from vllm.model_executor.layers.quantization.modelopt import (
     ModelOptNvFp4Config,
 )
 from vllm.model_executor.layers.quantization.online.base import OnlineQuantizationConfig
+from vllm.model_executor.layers.quantization.quark.quark import QuarkConfig
 from vllm.models.qwen4_exp.amd import ple_layer as amd_ple_layer
 from vllm.models.qwen4_exp.amd.ple_layer import (
     Qwen4ExpPLELayer as Qwen4ExpPLELayerAMD,
@@ -585,6 +586,16 @@ def test_ple_embedding_respects_inc_layer_config() -> None:
         Qwen4ExpPLEEmbeddingMethod.from_quant_config(quant_config, prefix)
 
 
+def test_ple_embedding_is_unquantized_under_quark() -> None:
+    prefix = "model.layers.1.ple.ple_embedding.ngram_embedding"
+    quant_config = QuarkConfig({"exclude": [], "global_quant_config": {}})
+
+    assert isinstance(
+        Qwen4ExpPLEEmbeddingMethod.from_quant_config(quant_config, prefix),
+        Qwen4ExpPLEUnquantizedEmbeddingMethod,
+    )
+
+
 def test_ple_embedding_dtype_overrides_modelopt_exclusion() -> None:
     prefix = "model.layers.1.ple.ple_embedding.ngram_embedding"
     quant_config = ModelOptNvFp4Config(exclude_modules=[prefix])

vllm/models/qwen4_exp/common/ngram_embedding.py

@@ -32,6 +32,7 @@ from vllm.model_executor.layers.quantization.modelopt import (
     ModelOptMixedPrecisionConfig,
     ModelOptQuantConfigBase,
 )
+from vllm.model_executor.layers.quantization.quark.quark import QuarkConfig
 from vllm.model_executor.layers.quantization.utils.fp8_utils import (
     create_fp8_scale_parameter,
 )
@@ -196,6 +197,9 @@ class Qwen4ExpPLEEmbeddingMethod(QuantizeMethodBase):
             and not quant_config.config_parser.resolve(None, prefix).quantized
         ):
             return Qwen4ExpPLEUnquantizedEmbeddingMethod()
+        # Quark quantizes only Linear and MoE layers; PLE tables stay BF16.
+        if isinstance(quant_config, QuarkConfig):
+            return Qwen4ExpPLEUnquantizedEmbeddingMethod()
         if not isinstance(quant_config, Fp8Config):
             raise NotImplementedError(
                 "Qwen4Exp PLE embedding does not support quantization config "