Index: uspace/drv/test/test1/test1.c
===================================================================
--- uspace/drv/test/test1/test1.c	(revision d5c1051faf4391647834d99babdd4a44ee5d9700)
+++ uspace/drv/test/test1/test1.c	(revision b7fd2a02e4161f4edd38548e7f8456b8021549be)
@@ -40,9 +40,9 @@
 #include "test1.h"
 
-static int test1_dev_add(ddf_dev_t *dev);
-static int test1_dev_remove(ddf_dev_t *dev);
-static int test1_dev_gone(ddf_dev_t *dev);
-static int test1_fun_online(ddf_fun_t *fun);
-static int test1_fun_offline(ddf_fun_t *fun);
+static errno_t test1_dev_add(ddf_dev_t *dev);
+static errno_t test1_dev_remove(ddf_dev_t *dev);
+static errno_t test1_dev_gone(ddf_dev_t *dev);
+static errno_t test1_fun_online(ddf_fun_t *fun);
+static errno_t test1_fun_offline(ddf_fun_t *fun);
 
 static driver_ops_t driver_ops = {
@@ -73,10 +73,10 @@
  * @param score Device match score.
  */
-static int register_fun_verbose(ddf_dev_t *parent, const char *message,
+static errno_t register_fun_verbose(ddf_dev_t *parent, const char *message,
     const char *name, const char *match_id, int match_score,
-    int expected_rc, ddf_fun_t **pfun)
+    errno_t expected_rc, ddf_fun_t **pfun)
 {
 	ddf_fun_t *fun = NULL;
-	int rc;
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "Registering function `%s': %s.", name, message);
@@ -141,10 +141,10 @@
  * @return Error code reporting success of the operation.
  */
-static int test1_dev_add(ddf_dev_t *dev)
+static errno_t test1_dev_add(ddf_dev_t *dev)
 {
 	ddf_fun_t *fun_a;
 	test1_t *test1;
 	const char *dev_name;
-	int rc;
+	errno_t rc;
 
 	dev_name = ddf_dev_get_name(dev);
@@ -196,7 +196,7 @@
 }
 
-static int fun_remove(ddf_fun_t *fun, const char *name)
-{
-	int rc;
+static errno_t fun_remove(ddf_fun_t *fun, const char *name)
+{
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "fun_remove(%p, '%s')", fun, name);
@@ -217,7 +217,7 @@
 }
 
-static int fun_unbind(ddf_fun_t *fun, const char *name)
-{
-	int rc;
+static errno_t fun_unbind(ddf_fun_t *fun, const char *name)
+{
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "fun_unbind(%p, '%s')", fun, name);
@@ -232,8 +232,8 @@
 }
 
-static int test1_dev_remove(ddf_dev_t *dev)
+static errno_t test1_dev_remove(ddf_dev_t *dev)
 {
 	test1_t *test1 = (test1_t *)ddf_dev_data_get(dev);
-	int rc;
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "test1_dev_remove(%p)", dev);
@@ -260,8 +260,8 @@
 }
 
-static int test1_dev_gone(ddf_dev_t *dev)
+static errno_t test1_dev_gone(ddf_dev_t *dev)
 {
 	test1_t *test1 = (test1_t *)ddf_dev_data_get(dev);
-	int rc;
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "test1_dev_remove(%p)", dev);
@@ -288,5 +288,5 @@
 }
 
-static int test1_fun_online(ddf_fun_t *fun)
+static errno_t test1_fun_online(ddf_fun_t *fun)
 {
 	ddf_msg(LVL_DEBUG, "test1_fun_online()");
@@ -294,5 +294,5 @@
 }
 
-static int test1_fun_offline(ddf_fun_t *fun)
+static errno_t test1_fun_offline(ddf_fun_t *fun)
 {
 	ddf_msg(LVL_DEBUG, "test1_fun_offline()");
Index: uspace/drv/test/test2/test2.c
===================================================================
--- uspace/drv/test/test2/test2.c	(revision d5c1051faf4391647834d99babdd4a44ee5d9700)
+++ uspace/drv/test/test2/test2.c	(revision b7fd2a02e4161f4edd38548e7f8456b8021549be)
@@ -40,9 +40,9 @@
 #define NAME "test2"
 
-static int test2_dev_add(ddf_dev_t *dev);
-static int test2_dev_remove(ddf_dev_t *dev);
-static int test2_dev_gone(ddf_dev_t *dev);
-static int test2_fun_online(ddf_fun_t *fun);
-static int test2_fun_offline(ddf_fun_t *fun);
+static errno_t test2_dev_add(ddf_dev_t *dev);
+static errno_t test2_dev_remove(ddf_dev_t *dev);
+static errno_t test2_dev_gone(ddf_dev_t *dev);
+static errno_t test2_fun_online(ddf_fun_t *fun);
+static errno_t test2_fun_offline(ddf_fun_t *fun);
 
 static driver_ops_t driver_ops = {
@@ -77,9 +77,9 @@
  * @param score Device match score.
  */
-static int register_fun_verbose(ddf_dev_t *parent, const char *message,
+static errno_t register_fun_verbose(ddf_dev_t *parent, const char *message,
     const char *name, const char *match_id, int match_score, ddf_fun_t **pfun)
 {
 	ddf_fun_t *fun;
-	int rc;
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "Registering function `%s': %s.", name, message);
@@ -118,9 +118,9 @@
  * @return Always EOK.
  */
-static int plug_unplug(void *arg)
+static errno_t plug_unplug(void *arg)
 {
 	test2_t *test2 = (test2_t *) arg;
 	ddf_fun_t *fun_a;
-	int rc;
+	errno_t rc;
 
 	async_usleep(1000);
@@ -157,7 +157,7 @@
 }
 
-static int fun_remove(ddf_fun_t *fun, const char *name)
-{
-	int rc;
+static errno_t fun_remove(ddf_fun_t *fun, const char *name)
+{
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "fun_remove(%p, '%s')", fun, name);
@@ -178,7 +178,7 @@
 }
 
-static int fun_unbind(ddf_fun_t *fun, const char *name)
-{
-	int rc;
+static errno_t fun_unbind(ddf_fun_t *fun, const char *name)
+{
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "fun_unbind(%p, '%s')", fun, name);
@@ -193,5 +193,5 @@
 }
 
-static int test2_dev_add(ddf_dev_t *dev)
+static errno_t test2_dev_add(ddf_dev_t *dev)
 {
 	test2_t *test2;
@@ -224,8 +224,8 @@
 }
 
-static int test2_dev_remove(ddf_dev_t *dev)
+static errno_t test2_dev_remove(ddf_dev_t *dev)
 {
 	test2_t *test2 = (test2_t *)ddf_dev_data_get(dev);
-	int rc;
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "test2_dev_remove(%p)", dev);
@@ -258,8 +258,8 @@
 }
 
-static int test2_dev_gone(ddf_dev_t *dev)
+static errno_t test2_dev_gone(ddf_dev_t *dev)
 {
 	test2_t *test2 = (test2_t *)ddf_dev_data_get(dev);
-	int rc;
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "test2_dev_gone(%p)", dev);
@@ -293,5 +293,5 @@
 
 
-static int test2_fun_online(ddf_fun_t *fun)
+static errno_t test2_fun_online(ddf_fun_t *fun)
 {
 	ddf_msg(LVL_DEBUG, "test2_fun_online()");
@@ -299,5 +299,5 @@
 }
 
-static int test2_fun_offline(ddf_fun_t *fun)
+static errno_t test2_fun_offline(ddf_fun_t *fun)
 {
 	ddf_msg(LVL_DEBUG, "test2_fun_offline()");
Index: uspace/drv/test/test3/test3.c
===================================================================
--- uspace/drv/test/test3/test3.c	(revision d5c1051faf4391647834d99babdd4a44ee5d9700)
+++ uspace/drv/test/test3/test3.c	(revision b7fd2a02e4161f4edd38548e7f8456b8021549be)
@@ -41,8 +41,8 @@
 #define NUM_FUNCS 20
 
-static int test3_dev_add(ddf_dev_t *dev);
-static int test3_dev_remove(ddf_dev_t *dev);
-static int test3_fun_online(ddf_fun_t *fun);
-static int test3_fun_offline(ddf_fun_t *fun);
+static errno_t test3_dev_add(ddf_dev_t *dev);
+static errno_t test3_dev_remove(ddf_dev_t *dev);
+static errno_t test3_fun_online(ddf_fun_t *fun);
+static errno_t test3_fun_offline(ddf_fun_t *fun);
 
 static driver_ops_t driver_ops = {
@@ -63,10 +63,10 @@
 } test3_t;
 
-static int register_fun_and_add_to_category(ddf_dev_t *parent,
+static errno_t register_fun_and_add_to_category(ddf_dev_t *parent,
     const char *base_name, size_t index, const char *class_name,
     ddf_fun_t **pfun)
 {
 	ddf_fun_t *fun = NULL;
-	int rc;
+	errno_t rc;
 	char *fun_name = NULL;
 	
@@ -106,7 +106,7 @@
 }
 
-static int fun_remove(ddf_fun_t *fun, const char *name)
+static errno_t fun_remove(ddf_fun_t *fun, const char *name)
 {
-	int rc;
+	errno_t rc;
 
 	ddf_msg(LVL_DEBUG, "fun_remove(%p, '%s')", fun, name);
@@ -127,7 +127,7 @@
 }
 
-static int test3_dev_add(ddf_dev_t *dev)
+static errno_t test3_dev_add(ddf_dev_t *dev)
 {
-	int rc = EOK;
+	errno_t rc = EOK;
 	test3_t *test3;
 
@@ -153,9 +153,9 @@
 }
 
-static int test3_dev_remove(ddf_dev_t *dev)
+static errno_t test3_dev_remove(ddf_dev_t *dev)
 {
 	test3_t *test3 = (test3_t *)ddf_dev_data_get(dev);
 	char *fun_name;
-	int rc;
+	errno_t rc;
 	size_t i;
 
@@ -176,5 +176,5 @@
 }
 
-static int test3_fun_online(ddf_fun_t *fun)
+static errno_t test3_fun_online(ddf_fun_t *fun)
 {
 	ddf_msg(LVL_DEBUG, "test3_fun_online()");
@@ -182,5 +182,5 @@
 }
 
-static int test3_fun_offline(ddf_fun_t *fun)
+static errno_t test3_fun_offline(ddf_fun_t *fun)
 {
 	ddf_msg(LVL_DEBUG, "test3_fun_offline()");