Index: uspace/drv/nic/e1k/e1k.c
===================================================================
--- uspace/drv/nic/e1k/e1k.c	(revision 38d150e6238ab44c861f6486e46454e07caeb0f0)
+++ uspace/drv/nic/e1k/e1k.c	(revision 071a1ddbcc6bb2b9c6f3c1a3acc865f1f23b5fe0)
@@ -1259,9 +1259,10 @@
  * @param nic Driver data
  *
- * @return IRQ capability handle if the handler was registered
+ * @param[out] handle  IRQ capability handle if the handler was registered
+ *
  * @return Negative error code otherwise
  *
  */
-inline static int e1000_register_int_handler(nic_t *nic)
+inline static int e1000_register_int_handler(nic_t *nic, cap_handle_t *handle)
 {
 	e1000_t *e1000 = DRIVER_DATA_NIC(nic);
@@ -1274,9 +1275,9 @@
 	e1000_irq_code.cmds[2].addr = e1000->reg_base_phys + E1000_IMC;
 	
-	int cap = register_interrupt_handler(nic_get_ddf_dev(nic), e1000->irq,
-	    e1000_interrupt_handler, &e1000_irq_code);
+	int rc = register_interrupt_handler(nic_get_ddf_dev(nic), e1000->irq,
+	    e1000_interrupt_handler, &e1000_irq_code, handle);
 	
 	fibril_mutex_unlock(&irq_reg_mutex);
-	return cap;
+	return rc;
 }
 
@@ -2164,7 +2165,7 @@
 	ddf_fun_set_ops(fun, &e1000_dev_ops);
 	
-	int irq_cap = e1000_register_int_handler(nic);
-	if (irq_cap < 0) {
-		rc = irq_cap;
+	int irq_cap;
+	rc = e1000_register_int_handler(nic, &irq_cap);
+	if (rc != EOK) {
 		goto err_fun_create;
 	}
Index: uspace/drv/nic/ne2k/ne2k.c
===================================================================
--- uspace/drv/nic/ne2k/ne2k.c	(revision 38d150e6238ab44c861f6486e46454e07caeb0f0)
+++ uspace/drv/nic/ne2k/ne2k.c	(revision 071a1ddbcc6bb2b9c6f3c1a3acc865f1f23b5fe0)
@@ -124,5 +124,5 @@
 static void ne2k_interrupt_handler(ipc_call_t *, ddf_dev_t *);
 
-static int ne2k_register_interrupt(nic_t *nic_data)
+static int ne2k_register_interrupt(nic_t *nic_data, cap_handle_t *handle)
 {
 	ne2k_t *ne2k = (ne2k_t *) nic_get_specific(nic_data);
@@ -160,7 +160,6 @@
 	}
 
-	int irq_cap = register_interrupt_handler(nic_get_ddf_dev(nic_data),
-		ne2k->irq, ne2k_interrupt_handler, &ne2k->code);
-	return irq_cap;
+	return register_interrupt_handler(nic_get_ddf_dev(nic_data),
+		ne2k->irq, ne2k_interrupt_handler, &ne2k->code, handle);
 }
 
@@ -228,6 +227,5 @@
 	ne2k->probed = true;
 	
-	int irq_cap = ne2k_register_interrupt(nic_data);
-	if (irq_cap < 0)
+	if (ne2k_register_interrupt(nic_data, NULL) != EOK)
 		return EINVAL;
 	
Index: uspace/drv/nic/rtl8139/driver.c
===================================================================
--- uspace/drv/nic/rtl8139/driver.c	(revision 38d150e6238ab44c861f6486e46454e07caeb0f0)
+++ uspace/drv/nic/rtl8139/driver.c	(revision 071a1ddbcc6bb2b9c6f3c1a3acc865f1f23b5fe0)
@@ -842,8 +842,9 @@
  *  @param nic_data  The driver data
  *
- *  @return IRQ capability handle if the handler was registered.
+ *  @param[out] handle  IRQ capability handle if the handler was registered.
+ *
  *  @return Negative error code otherwise.
  */
-inline static int rtl8139_register_int_handler(nic_t *nic_data)
+inline static int rtl8139_register_int_handler(nic_t *nic_data, cap_handle_t *handle)
 {
 	rtl8139_t *rtl8139 = nic_get_specific(nic_data);
@@ -856,10 +857,10 @@
 	rtl8139_irq_code.cmds[2].addr = rtl8139->io_addr + ISR;
 	rtl8139_irq_code.cmds[3].addr = rtl8139->io_addr + IMR;
-	int cap = register_interrupt_handler(nic_get_ddf_dev(nic_data),
-	    rtl8139->irq, rtl8139_interrupt_handler, &rtl8139_irq_code);
+	int rc = register_interrupt_handler(nic_get_ddf_dev(nic_data),
+	    rtl8139->irq, rtl8139_interrupt_handler, &rtl8139_irq_code, handle);
 
 	RTL8139_IRQ_STRUCT_UNLOCK();
 
-	return cap;
+	return rc;
 }
 
@@ -1287,7 +1288,7 @@
 
 	/* Register interrupt handler */
-	int irq_cap = rtl8139_register_int_handler(nic_data);
-	if (irq_cap < 0) {
-		rc = irq_cap;
+	int irq_cap;
+	rc = rtl8139_register_int_handler(nic_data, &irq_cap);
+	if (rc != EOK) {
 		goto err_pio;
 	}
Index: uspace/drv/nic/rtl8169/driver.c
===================================================================
--- uspace/drv/nic/rtl8169/driver.c	(revision 38d150e6238ab44c861f6486e46454e07caeb0f0)
+++ uspace/drv/nic/rtl8169/driver.c	(revision 071a1ddbcc6bb2b9c6f3c1a3acc865f1f23b5fe0)
@@ -73,5 +73,5 @@
 static void rtl8169_send_frame(nic_t *nic_data, void *data, size_t size);
 static void rtl8169_irq_handler(ipc_call_t *icall, ddf_dev_t *dev);
-static inline int rtl8169_register_int_handler(nic_t *nic_data);
+static inline int rtl8169_register_int_handler(nic_t *nic_data, cap_handle_t *handle);
 static inline void rtl8169_get_hwaddr(rtl8169_t *rtl8169, nic_address_t *addr);
 static inline void rtl8169_set_hwaddr(rtl8169_t *rtl8169, const nic_address_t *addr);
@@ -359,5 +359,5 @@
 }
 
-inline static int rtl8169_register_int_handler(nic_t *nic_data)
+inline static int rtl8169_register_int_handler(nic_t *nic_data, cap_handle_t *handle)
 {
 	rtl8169_t *rtl8169 = nic_get_specific(nic_data);
@@ -367,8 +367,8 @@
 	rtl8169_irq_code.cmds[2].addr = rtl8169->regs + ISR;
 	rtl8169_irq_code.cmds[3].addr = rtl8169->regs + IMR;
-	int irq_cap = register_interrupt_handler(nic_get_ddf_dev(nic_data),
-	    rtl8169->irq, rtl8169_irq_handler, &rtl8169_irq_code);
-
-	return irq_cap;
+	int rc = register_interrupt_handler(nic_get_ddf_dev(nic_data),
+	    rtl8169->irq, rtl8169_irq_handler, &rtl8169_irq_code, handle);
+
+	return rc;
 }
 
@@ -427,7 +427,7 @@
 		goto err_pio;
 
-	int irq_cap = rtl8169_register_int_handler(nic_data);
-	if (irq_cap < 0) {
-		rc = irq_cap;
+	int irq_cap;
+	rc = rtl8169_register_int_handler(nic_data, &irq_cap);
+	if (rc != EOK) {
 		ddf_msg(LVL_ERROR, "Failed to register IRQ handler (%d)", rc);
 		goto err_irq;