diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index c0b857fbd4..380976a066 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -440,27 +440,33 @@ DeviceState *qdev_find_recursive(BusState *bus, const char *id)
 static void qbus_realize(BusState *bus, DeviceState *parent, const char *name)
 {
     const char *typename = object_get_typename(OBJECT(bus));
+    BusClass *bc;
     char *buf;
-    int i,len;
+    int i, len, bus_id;
 
     bus->parent = parent;
 
     if (name) {
         bus->name = g_strdup(name);
     } else if (bus->parent && bus->parent->id) {
-        /* parent device has id -> use it for bus name */
+        /* parent device has id -> use it plus parent-bus-id for bus name */
+        bus_id = bus->parent->num_child_bus;
+
         len = strlen(bus->parent->id) + 16;
         buf = g_malloc(len);
-        snprintf(buf, len, "%s.%d", bus->parent->id, bus->parent->num_child_bus);
+        snprintf(buf, len, "%s.%d", bus->parent->id, bus_id);
         bus->name = buf;
     } else {
-        /* no id -> use lowercase bus type for bus name */
+        /* no id -> use lowercase bus type plus global bus-id for bus name */
+        bc = BUS_GET_CLASS(bus);
+        bus_id = bc->automatic_ids++;
+
         len = strlen(typename) + 16;
         buf = g_malloc(len);
-        len = snprintf(buf, len, "%s.%d", typename,
-                       bus->parent ? bus->parent->num_child_bus : 0);
-        for (i = 0; i < len; i++)
+        len = snprintf(buf, len, "%s.%d", typename, bus_id);
+        for (i = 0; i < len; i++) {
             buf[i] = qemu_tolower(buf[i]);
+        }
         bus->name = buf;
     }
 
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index d5dc1ef336..ae1699d6db 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -221,10 +221,16 @@ static void pc_init1(QEMUMachineInitArgs *args,
     } else {
         for(i = 0; i < MAX_IDE_BUS; i++) {
             ISADevice *dev;
+            char busname[] = "ide.0";
             dev = isa_ide_init(isa_bus, ide_iobase[i], ide_iobase2[i],
                                ide_irq[i],
                                hd[MAX_IDE_DEVS * i], hd[MAX_IDE_DEVS * i + 1]);
-            idebus[i] = qdev_get_child_bus(DEVICE(dev), "ide.0");
+            /*
+             * The ide bus name is ide.0 for the first bus and ide.1 for the
+             * second one.
+             */
+            busname[4] = '0' + i;
+            idebus[i] = qdev_get_child_bus(DEVICE(dev), busname);
         }
     }
 
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 276b336c09..1ed0691716 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -176,6 +176,8 @@ struct BusClass {
     void (*reset)(BusState *bus);
     /* maximum devices allowed on the bus, 0: no limit. */
     int max_dev;
+    /* number of automatically allocated bus ids (e.g. ide.0) */
+    int automatic_ids;
 };
 
 typedef struct BusChild {