diff --git a/hgsane/sane_hg_mdw.cpp b/hgsane/sane_hg_mdw.cpp
index 8922c9e..0fe4d27 100644
--- a/hgsane/sane_hg_mdw.cpp
+++ b/hgsane/sane_hg_mdw.cpp
@@ -1149,6 +1149,9 @@ SANE_Option_Descriptor* hg_sane_middleware::from_json(scanner_handle h, const st
 		}
 		ret->size = bytes;
 
+		if (jsn->get_value("auto", bv) && !bv)
+			ret->cap &= ~SANE_CAP_AUTOMATIC;
+
 		if (jsn->get_value("readonly", bv) && bv)
 			SET_CAP_READONLY(ret->cap)
 
@@ -1478,7 +1481,7 @@ bool hg_sane_middleware::get_current_value(scanner_handle handle, const void* op
 
 	return ret;
 }
-void* hg_sane_middleware::get_default_value(scanner_handle handle, const void* option, int* bytes, bool log)
+void* hg_sane_middleware::get_default_value(scanner_handle handle, const void* option, int* bytes, bool log, bool* can_auto)
 {
 	std::string val(get_option_json(handle, (void *)option));
 	void* data = nullptr;
@@ -1487,6 +1490,15 @@ void* hg_sane_middleware::get_default_value(scanner_handle handle, const void* o
 	if (jsn->attach_text(&val[0]) &&
 		jsn->get_value("type", val))
 	{
+		if (can_auto)
+		{
+			bool yes = false;
+
+			*can_auto = true;
+			if (jsn->get_value("auto", yes))
+				*can_auto = yes;
+		}
+
 		std::string title(hg_sane_middleware::get_string_in_json(jsn, "title"));
 		if (val == "bool")
 		{
@@ -1867,11 +1879,17 @@ SANE_Status hg_sane_middleware::set_option(SANE_Handle h, const void* option, SA
 		{
 			VLOG_MINI_2(LOG_LEVEL_WARNING, "Option %d(%s) call SANE_ACTION_SET_AUTO, we set default value.\n", option, desc->title);
 
-			int len = 0;
-			void* val = get_default_value(handle, option, &len);
+			int		len = 0;
+			bool	can_auto = true;
+			void*	val = get_default_value(handle, option, &len, false, &can_auto);
+
+			if (!val || !can_auto)
+			{
+				if(val)
+					local_utility::free_memory(val);
 
-			if (!val)
 				return SANE_STATUS_UNSUPPORTED;
+			}
 
 			if (value)
 			{
diff --git a/hgsane/sane_hg_mdw.h b/hgsane/sane_hg_mdw.h
index b790da2..039f1fb 100644
--- a/hgsane/sane_hg_mdw.h
+++ b/hgsane/sane_hg_mdw.h
@@ -150,7 +150,7 @@ class hg_sane_middleware
 
 	void reload_current_value(scanner_handle handle, std::vector<std::string>* changed = NULL);
 	bool get_current_value(scanner_handle handle, const void* option, void(*setv)(void*, size_t, void*), void* value, SANE_Value_Type* type = NULL);
-	void* get_default_value(scanner_handle handle, const void* option, int* bytes = nullptr, bool log = false);	// caller should call local_utility::free_memory to free the returned value
+	void* get_default_value(scanner_handle handle, const void* option, int* bytes = nullptr, bool log = false, bool* can_auto = nullptr);	// caller should call local_utility::free_memory to free the returned value
 
 /// <summary>
 /// 关联项处理