diff --git a/hw/pc_piix.c b/hw/pc_piix.c
index 6a75718..be809db 100644
--- a/hw/pc_piix.c
+++ b/hw/pc_piix.c
@@ -378,7 +378,7 @@ static QEMUMachine pc_machine_v1_1 = {
             .property = "vapic",\
             .value    = "off",\
         },{\
-            .driver   = "USB",\
+            .driver   = TYPE_USB_DEVICE,\
             .property = "full-path",\
             .value    = "no",\
         }
@@ -451,7 +451,7 @@ static QEMUMachine pc_machine_v0_14 = {
 #define PC_COMPAT_0_13 \
         PC_COMPAT_0_14,\
         {\
-            .driver   = "PCI",\
+            .driver   = TYPE_PCI_DEVICE,\
             .property = "command_serr_enable",\
             .value    = "off",\
         },{\
diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index 0c6dade..ddd7b25 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -1158,10 +1158,14 @@ void qdev_prop_set_globals(DeviceState *dev)
     GlobalProperty *prop;
 
     QTAILQ_FOREACH(prop, &global_props, next) {
-        if (strcmp(object_get_typename(OBJECT(dev)), prop->driver) != 0) {
+        Object *obj;
+
+        obj = object_dynamic_cast(OBJECT(dev), prop->driver);
+        if (obj == NULL) {
             continue;
         }
-        if (qdev_prop_parse(dev, prop->property, prop->value) != 0) {
+
+        if (qdev_prop_parse(DEVICE(obj), prop->property, prop->value) != 0) {
             exit(1);
         }
     }