Index: uspace/lib/drv/include/ops/battery_dev.h
===================================================================
--- uspace/lib/drv/include/ops/battery_dev.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/lib/drv/include/ops/battery_dev.h	(revision 08d4ea2111e5db01d0a6194bd9da4248ee282dc7)
@@ -40,6 +40,6 @@
 
 typedef struct {
-	int (*battery_status_get)(ddf_fun_t *, battery_status_t *);
-	int (*battery_charge_level_get)(ddf_fun_t *, int *);
+	errno_t (*battery_status_get)(ddf_fun_t *, battery_status_t *);
+	errno_t (*battery_charge_level_get)(ddf_fun_t *, int *);
 } battery_dev_ops_t;
 
Index: uspace/lib/drv/include/ops/clock_dev.h
===================================================================
--- uspace/lib/drv/include/ops/clock_dev.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/lib/drv/include/ops/clock_dev.h	(revision 08d4ea2111e5db01d0a6194bd9da4248ee282dc7)
@@ -40,6 +40,6 @@
 
 typedef struct {
-	int (*time_get)(ddf_fun_t *, struct tm *);
-	int (*time_set)(ddf_fun_t *, struct tm *);
+	errno_t (*time_get)(ddf_fun_t *, struct tm *);
+	errno_t (*time_set)(ddf_fun_t *, struct tm *);
 } clock_dev_ops_t;
 
Index: uspace/lib/drv/include/ops/hw_res.h
===================================================================
--- uspace/lib/drv/include/ops/hw_res.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/lib/drv/include/ops/hw_res.h	(revision 08d4ea2111e5db01d0a6194bd9da4248ee282dc7)
@@ -44,9 +44,9 @@
 typedef struct {
 	hw_resource_list_t *(*get_resource_list)(ddf_fun_t *);
-	int (*enable_interrupt)(ddf_fun_t *, int);
-	int (*disable_interrupt)(ddf_fun_t *, int);
-	int (*clear_interrupt)(ddf_fun_t *, int);
-	int (*dma_channel_setup)(ddf_fun_t *, unsigned, uint32_t, uint32_t, uint8_t);
-	int (*dma_channel_remain)(ddf_fun_t *, unsigned, size_t *);
+	errno_t (*enable_interrupt)(ddf_fun_t *, int);
+	errno_t (*disable_interrupt)(ddf_fun_t *, int);
+	errno_t (*clear_interrupt)(ddf_fun_t *, int);
+	errno_t (*dma_channel_setup)(ddf_fun_t *, unsigned, uint32_t, uint32_t, uint8_t);
+	errno_t (*dma_channel_remain)(ddf_fun_t *, unsigned, size_t *);
 } hw_res_ops_t;
 
Index: uspace/lib/drv/include/ops/ieee80211.h
===================================================================
--- uspace/lib/drv/include/ops/ieee80211.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/lib/drv/include/ops/ieee80211.h	(revision 08d4ea2111e5db01d0a6194bd9da4248ee282dc7)
@@ -51,5 +51,5 @@
 	 *
 	 */
-	int (*get_scan_results)(ddf_fun_t *, ieee80211_scan_results_t *, bool);
+	errno_t (*get_scan_results)(ddf_fun_t *, ieee80211_scan_results_t *, bool);
 	
 	/** Connect IEEE 802.11 device to specified network.
@@ -62,5 +62,5 @@
 	 *
 	 */
-	int (*connect)(ddf_fun_t *, char *, char *);
+	errno_t (*connect)(ddf_fun_t *, char *, char *);
 	
 	/** Disconnect IEEE 802.11 device from network.
@@ -71,5 +71,5 @@
 	 *
 	 */
-	int (*disconnect)(ddf_fun_t *);
+	errno_t (*disconnect)(ddf_fun_t *);
 } ieee80211_iface_t;
 
Index: uspace/lib/drv/include/ops/led_dev.h
===================================================================
--- uspace/lib/drv/include/ops/led_dev.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/lib/drv/include/ops/led_dev.h	(revision 08d4ea2111e5db01d0a6194bd9da4248ee282dc7)
@@ -40,5 +40,5 @@
 
 typedef struct {
-	int (*color_set)(ddf_fun_t *, pixel_t);
+	errno_t (*color_set)(ddf_fun_t *, pixel_t);
 } led_dev_ops_t;
 
Index: uspace/lib/drv/include/ops/nic.h
===================================================================
--- uspace/lib/drv/include/ops/nic.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/lib/drv/include/ops/nic.h	(revision 08d4ea2111e5db01d0a6194bd9da4248ee282dc7)
@@ -44,68 +44,68 @@
 typedef struct nic_iface {
 	/** Mandatory methods */
-	int (*send_frame)(ddf_fun_t *, void *, size_t);
-	int (*callback_create)(ddf_fun_t *);
-	int (*get_state)(ddf_fun_t *, nic_device_state_t *);
-	int (*set_state)(ddf_fun_t *, nic_device_state_t);
-	int (*get_address)(ddf_fun_t *, nic_address_t *);
+	errno_t (*send_frame)(ddf_fun_t *, void *, size_t);
+	errno_t (*callback_create)(ddf_fun_t *);
+	errno_t (*get_state)(ddf_fun_t *, nic_device_state_t *);
+	errno_t (*set_state)(ddf_fun_t *, nic_device_state_t);
+	errno_t (*get_address)(ddf_fun_t *, nic_address_t *);
 	
 	/** Optional methods */
-	int (*set_address)(ddf_fun_t *, const nic_address_t *);
-	int (*get_stats)(ddf_fun_t *, nic_device_stats_t *);
-	int (*get_device_info)(ddf_fun_t *, nic_device_info_t *);
-	int (*get_cable_state)(ddf_fun_t *, nic_cable_state_t *);
+	errno_t (*set_address)(ddf_fun_t *, const nic_address_t *);
+	errno_t (*get_stats)(ddf_fun_t *, nic_device_stats_t *);
+	errno_t (*get_device_info)(ddf_fun_t *, nic_device_info_t *);
+	errno_t (*get_cable_state)(ddf_fun_t *, nic_cable_state_t *);
 	
-	int (*get_operation_mode)(ddf_fun_t *, int *, nic_channel_mode_t *,
+	errno_t (*get_operation_mode)(ddf_fun_t *, int *, nic_channel_mode_t *,
 	    nic_role_t *);
-	int (*set_operation_mode)(ddf_fun_t *, int, nic_channel_mode_t,
+	errno_t (*set_operation_mode)(ddf_fun_t *, int, nic_channel_mode_t,
 	    nic_role_t);
-	int (*autoneg_enable)(ddf_fun_t *, uint32_t);
-	int (*autoneg_disable)(ddf_fun_t *);
-	int (*autoneg_probe)(ddf_fun_t *, uint32_t *, uint32_t *,
+	errno_t (*autoneg_enable)(ddf_fun_t *, uint32_t);
+	errno_t (*autoneg_disable)(ddf_fun_t *);
+	errno_t (*autoneg_probe)(ddf_fun_t *, uint32_t *, uint32_t *,
 	    nic_result_t *, nic_result_t *);
-	int (*autoneg_restart)(ddf_fun_t *);
-	int (*get_pause)(ddf_fun_t *, nic_result_t *, nic_result_t *,
+	errno_t (*autoneg_restart)(ddf_fun_t *);
+	errno_t (*get_pause)(ddf_fun_t *, nic_result_t *, nic_result_t *,
 		uint16_t *);
-	int (*set_pause)(ddf_fun_t *, int, int, uint16_t);
+	errno_t (*set_pause)(ddf_fun_t *, int, int, uint16_t);
 	
-	int (*unicast_get_mode)(ddf_fun_t *, nic_unicast_mode_t *, size_t,
+	errno_t (*unicast_get_mode)(ddf_fun_t *, nic_unicast_mode_t *, size_t,
 	    nic_address_t *, size_t *);
-	int (*unicast_set_mode)(ddf_fun_t *, nic_unicast_mode_t,
+	errno_t (*unicast_set_mode)(ddf_fun_t *, nic_unicast_mode_t,
 	    const nic_address_t *, size_t);
-	int (*multicast_get_mode)(ddf_fun_t *, nic_multicast_mode_t *, size_t,
+	errno_t (*multicast_get_mode)(ddf_fun_t *, nic_multicast_mode_t *, size_t,
 	    nic_address_t *, size_t *);
-	int (*multicast_set_mode)(ddf_fun_t *, nic_multicast_mode_t,
+	errno_t (*multicast_set_mode)(ddf_fun_t *, nic_multicast_mode_t,
 	    const nic_address_t *, size_t);
-	int (*broadcast_get_mode)(ddf_fun_t *, nic_broadcast_mode_t *);
-	int (*broadcast_set_mode)(ddf_fun_t *, nic_broadcast_mode_t);
-	int (*defective_get_mode)(ddf_fun_t *, uint32_t *);
-	int (*defective_set_mode)(ddf_fun_t *, uint32_t);
-	int (*blocked_sources_get)(ddf_fun_t *, size_t, nic_address_t *,
+	errno_t (*broadcast_get_mode)(ddf_fun_t *, nic_broadcast_mode_t *);
+	errno_t (*broadcast_set_mode)(ddf_fun_t *, nic_broadcast_mode_t);
+	errno_t (*defective_get_mode)(ddf_fun_t *, uint32_t *);
+	errno_t (*defective_set_mode)(ddf_fun_t *, uint32_t);
+	errno_t (*blocked_sources_get)(ddf_fun_t *, size_t, nic_address_t *,
 	    size_t *);
-	int (*blocked_sources_set)(ddf_fun_t *, const nic_address_t *, size_t);
+	errno_t (*blocked_sources_set)(ddf_fun_t *, const nic_address_t *, size_t);
 	
-	int (*vlan_get_mask)(ddf_fun_t *, nic_vlan_mask_t *);
-	int (*vlan_set_mask)(ddf_fun_t *, const nic_vlan_mask_t *);
-	int (*vlan_set_tag)(ddf_fun_t *, uint16_t, bool, bool);
+	errno_t (*vlan_get_mask)(ddf_fun_t *, nic_vlan_mask_t *);
+	errno_t (*vlan_set_mask)(ddf_fun_t *, const nic_vlan_mask_t *);
+	errno_t (*vlan_set_tag)(ddf_fun_t *, uint16_t, bool, bool);
 	
-	int (*wol_virtue_add)(ddf_fun_t *, nic_wv_type_t, const void *,
+	errno_t (*wol_virtue_add)(ddf_fun_t *, nic_wv_type_t, const void *,
 	    size_t, nic_wv_id_t *);
-	int (*wol_virtue_remove)(ddf_fun_t *, nic_wv_id_t);
-	int (*wol_virtue_probe)(ddf_fun_t *, nic_wv_id_t, nic_wv_type_t *,
+	errno_t (*wol_virtue_remove)(ddf_fun_t *, nic_wv_id_t);
+	errno_t (*wol_virtue_probe)(ddf_fun_t *, nic_wv_id_t, nic_wv_type_t *,
 	    size_t, void *, size_t *);
-	int (*wol_virtue_list)(ddf_fun_t *, nic_wv_type_t, size_t,
+	errno_t (*wol_virtue_list)(ddf_fun_t *, nic_wv_type_t, size_t,
 	    nic_wv_id_t *, size_t *);
-	int (*wol_virtue_get_caps)(ddf_fun_t *, nic_wv_type_t, int *);
-	int (*wol_load_info)(ddf_fun_t *, nic_wv_type_t *, size_t,
+	errno_t (*wol_virtue_get_caps)(ddf_fun_t *, nic_wv_type_t, int *);
+	errno_t (*wol_load_info)(ddf_fun_t *, nic_wv_type_t *, size_t,
 	    uint8_t *, size_t *);
 	
-	int (*offload_probe)(ddf_fun_t *, uint32_t *, uint32_t *);
-	int (*offload_set)(ddf_fun_t *, uint32_t, uint32_t);
+	errno_t (*offload_probe)(ddf_fun_t *, uint32_t *, uint32_t *);
+	errno_t (*offload_set)(ddf_fun_t *, uint32_t, uint32_t);
 	
-	int (*poll_get_mode)(ddf_fun_t *, nic_poll_mode_t *,
+	errno_t (*poll_get_mode)(ddf_fun_t *, nic_poll_mode_t *,
 	    struct timeval *);
-	int (*poll_set_mode)(ddf_fun_t *, nic_poll_mode_t,
+	errno_t (*poll_set_mode)(ddf_fun_t *, nic_poll_mode_t,
 	    const struct timeval *);
-	int (*poll_now)(ddf_fun_t *);
+	errno_t (*poll_now)(ddf_fun_t *);
 } nic_iface_t;