Index: uspace/drv/bus/usb/xhci/endpoint.c
===================================================================
--- uspace/drv/bus/usb/xhci/endpoint.c	(revision fbfe59dafcc4f7e06cbbf09e2d88ed3e434b4a33)
+++ uspace/drv/bus/usb/xhci/endpoint.c	(revision 60876fd36c87b1471e4642d8d42e8bcf02d9d066)
@@ -102,5 +102,7 @@
 	if (dev->speed >= USB_SPEED_HIGH ||
 	    ep->transfer_type != USB_TRANSFER_INTERRUPT) {
-		xhci_ep->interval = 1 << (xhci_ep->interval - 1);
+
+		if (xhci_ep->interval > 0)
+			xhci_ep->interval = 1 << (xhci_ep->interval - 1);
 	}