[Eager] Add _fallback_legacy_dygraph for npu/xpu/rocm (#41774) (#41898)

* [Eager] add _fallback_legacy_dygraph for npu/xpu/rocm

* fix import

python/paddle/fluid/framework.py

@@ -166,6 +166,40 @@ def _in_eager_without_dygraph_check():
     return _in_eager_mode_
 
 
+# FIXME(dev): We haven't fully verified eager mode on XPU/NPU et.al but
+# only GPU/CPU. Remove this after we improve this feature.
+_is_first_import_ = True
+
+
+def _fallback_legacy_dygraph():
+    global _in_eager_mode_
+    global _is_first_import_
+    need_fallback = False
+    # Only enable eager on CPU/GPU
+    is_not_support = core.is_compiled_with_xpu() or core.is_compiled_with_npu(
+    ) or core.is_compiled_with_ipu() or core.is_compiled_with_mlu(
+    ) or core.is_compiled_with_rocm()
+
+    if _in_eager_mode_ and is_not_support:
+        # switch into legacy dygraph mode
+        warnings.warn(
+            "We will fallback into legacy dygraph on NPU/XPU/MLU/IPU/ROCM devices. Because we only support new eager dygraph mode on CPU/GPU currently. "
+        )
+        _in_eager_mode_ = False
+        if not _is_first_import_:
+            _enable_legacy_dygraph()
+        need_fallback = True
+
+    need_fallback = False
+    _is_first_import_ = False
+
+    return need_fallback
+
+
+# switch into legacy mode if need while import paddle
+_fallback_legacy_dygraph()
+
+
 def in_dygraph_mode():
     """
 
@@ -206,11 +240,16 @@ def _non_static_mode():
 
 @signature_safe_contextmanager
 def _test_eager_guard(place=None):
-    _disable_legacy_dygraph()
+    # FIXME(dev): We haven't fully verified eager mode on XPU/NPU et.al but
+    # only GPU/CPU. Remove this after we improve this feature.
+    already_fallback = _fallback_legacy_dygraph()
+    if not already_fallback:
+        _disable_legacy_dygraph()
     try:
         yield
     finally:
-        _enable_legacy_dygraph()
+        if not already_fallback:
+            _enable_legacy_dygraph()
 
 
 global_ipu_index = None