diff -r 3b7eec329112 -r 8fede404c01f master/domain.c
--- a/master/domain.c	Wed Oct 25 16:53:17 2006 +0000
+++ b/master/domain.c	Thu Oct 26 16:29:26 2006 +0000
@@ -139,8 +139,6 @@
 
     domain = container_of(kobj, ec_domain_t, kobj);
 
-    EC_INFO("Clearing domain %i.\n", domain->index);
-
     list_for_each_entry_safe(datagram, next, &domain->datagrams, list) {
         ec_datagram_clear(datagram);
         kfree(datagram);
@@ -222,6 +220,9 @@
     data_reg->data_ptr = data_ptr;
 
     list_add_tail(&data_reg->list, &domain->data_regs);
+
+    ec_slave_request_state(slave, EC_SLAVE_STATE_OP);
+
     return 0;
 }
 
@@ -297,6 +298,9 @@
     }
 
     list_add_tail(&data_reg->list, &domain->data_regs);
+
+    ec_slave_request_state(slave, EC_SLAVE_STATE_OP);
+
     return 0;
 }
 
@@ -448,7 +452,7 @@
    Places all process data datagrams in the masters datagram queue.
 */
 
-void ec_domain_queue(ec_domain_t *domain /**< EtherCAT domain */)
+void ec_domain_queue_datagrams(ec_domain_t *domain /**< EtherCAT domain */)
 {
     ec_datagram_t *datagram;
 
@@ -460,6 +464,22 @@
 /*****************************************************************************/
 
 /**
+   Dequeues all datagrams from the masters datagram queue.
+*/
+
+void ec_domain_dequeue_datagrams(ec_domain_t *domain /**< EtherCAT domain */)
+{
+    ec_datagram_t *datagram;
+
+    list_for_each_entry(datagram, &domain->datagrams, list) {
+        if (!list_empty(&datagram->queue)) // datagram queued?
+            list_del_init(&datagram->queue);
+    }
+}
+
+/*****************************************************************************/
+
+/**
    Formats attribute data for SysFS reading.
    \return number of bytes to read
 */
@@ -518,18 +538,15 @@
     if (!(slave = ecrt_master_get_slave(master, address))) return NULL;
     if (ec_slave_validate(slave, vendor_id, product_code)) return NULL;
 
-    if (!data_ptr) {
-        // data_ptr is NULL => mark slave as "registered" (do not warn)
-        slave->registered = 1;
-    }
+    if (!data_ptr) return slave;
 
     list_for_each_entry(pdo, &slave->sii_pdos, list) {
         list_for_each_entry(entry, &pdo->entries, list) {
             if (entry->index != pdo_index
                 || entry->subindex != pdo_subindex) continue;
 
-            if (data_ptr) {
-                ec_domain_reg_pdo_entry(domain, slave, pdo, entry, data_ptr);
+            if (ec_domain_reg_pdo_entry(domain, slave, pdo, entry, data_ptr)) {
+                return NULL;
             }
 
             return slave;
@@ -538,7 +555,6 @@
 
     EC_ERR("Slave %i does not provide PDO 0x%04X:%i.\n",
            slave->ring_position, pdo_index, pdo_subindex);
-    slave->registered = 0;
     return NULL;
 }
 
@@ -609,11 +625,7 @@
     if (!(slave = ecrt_master_get_slave(master, address))) return NULL;
     if (ec_slave_validate(slave, vendor_id, product_code)) return NULL;
 
-    if (!data_ptr) {
-        // data_ptr is NULL => mark slave as "registered" (do not warn)
-        slave->registered = 1;
-        return slave;
-    }
+    if (!data_ptr) return slave;
 
     if (ec_domain_reg_pdo_range(domain, slave,
                                 direction, offset, length, data_ptr)) {
@@ -666,7 +678,7 @@
         domain->working_counter_changes = 0;
     }
 
-    ec_domain_queue(domain);
+    ec_domain_queue_datagrams(domain);
 }
 
 /*****************************************************************************/