Index: uspace/lib/usbhost/src/ddf_helpers.c
===================================================================
--- uspace/lib/usbhost/src/ddf_helpers.c	(revision 78188e5873f47aad1ea0bb8b9e68b6f694b89dc4)
+++ uspace/lib/usbhost/src/ddf_helpers.c	(revision e7c4115de0a5bf1dd17b4e273352cc4607d67e03)
@@ -748,5 +748,6 @@
  * @param[in] gen_irq_code IRQ code generator.
  *
- * @return EOK on success or negative error code
+ * @return IRQ kernel object capability on success.
+ * @return Negative error code.
  */
 int hcd_ddf_setup_interrupts(ddf_dev_t *device,
@@ -770,22 +771,22 @@
 
 	/* Register handler to avoid interrupt lockup */
-	int ret = register_interrupt_handler(device, irq, handler, &irq_code);
+	const int irq_cap = register_interrupt_handler(device, irq, handler,
+	    &irq_code);
 	irq_code_clean(&irq_code);
+	if (irq_cap < 0) {
+		usb_log_error("Failed to register interrupt handler: %s.\n",
+		    str_error(irq_cap));
+		return irq_cap;
+	}
+
+	/* Enable interrupts */
+	int ret = hcd_ddf_enable_interrupts(device);
 	if (ret != EOK) {
 		usb_log_error("Failed to register interrupt handler: %s.\n",
 		    str_error(ret));
-		return ret;
-	}
-
-	/* Enable interrupts */
-	ret = hcd_ddf_enable_interrupts(device);
-	if (ret != EOK) {
-		usb_log_error("Failed to register interrupt handler: %s.\n",
-		    str_error(ret));
-		unregister_interrupt_handler(device, irq);
-		return ret;
-	}
-	assert(irq > 0);
-	return irq;
+		unregister_interrupt_handler(device, irq_cap);
+		return ret;
+	}
+	return irq_cap;
 }
 
@@ -882,7 +883,8 @@
 	interrupt_handler_t *irq_handler =
 	    driver->irq_handler ? driver->irq_handler : ddf_hcd_gen_irq_handler;
-	const int irq = hcd_ddf_setup_interrupts(device, &hw_res, irq_handler,
-	    driver->irq_code_gen);
-	if (!(irq < 0)) {
+	const int irq_cap = hcd_ddf_setup_interrupts(device, &hw_res,
+	    irq_handler, driver->irq_code_gen);
+	bool irqs_enabled = !(irq_cap < 0);
+	if (irqs_enabled) {
 		usb_log_debug("Hw interrupts enabled.\n");
 	}
@@ -899,5 +901,5 @@
 	/* Init hw driver */
 	hcd_t *hcd = dev_to_hcd(device);
-	ret = driver->init(hcd, &hw_res, !(irq < 0));
+	ret = driver->init(hcd, &hw_res, irqs_enabled);
 	hw_res_list_parsed_clean(&hw_res);
 	if (ret != EOK) {
@@ -907,5 +909,5 @@
 
 	/* Need working irq replacement to setup root hub */
-	if ((irq < 0) && hcd->ops.status_hook) {
+	if (!irqs_enabled && hcd->ops.status_hook) {
 		hcd->polling_fibril = fibril_create(interrupt_polling, hcd);
 		if (hcd->polling_fibril == 0) {
@@ -916,5 +918,5 @@
 		fibril_add_ready(hcd->polling_fibril);
 		usb_log_warning("Failed to enable interrupts: %s."
-		    " Falling back to polling.\n", str_error(irq));
+		    " Falling back to polling.\n", str_error(irq_cap));
 	}
 
@@ -930,5 +932,5 @@
 irq_unregister:
 		/* Unregistering non-existent should be ok */
-		unregister_interrupt_handler(device, irq);
+		unregister_interrupt_handler(device, irq_cap);
 		hcd_ddf_clean_hc(device);
 		return ret;