diff --git a/sys/bus/usb/usbdi.c b/sys/bus/usb/usbdi.c
index 014fa1b..2d7286a 100644
--- a/sys/bus/usb/usbdi.c
+++ b/sys/bus/usb/usbdi.c
@@ -41,6 +41,7 @@
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/kernel.h>
 #include <sys/module.h>
 #include <sys/bus.h>
 #include "usb_if.h"
@@ -326,10 +327,12 @@ usbd_transfer(usbd_xfer_handle xfer)
 	if (err != USBD_IN_PROGRESS)
 		return (err);
 	crit_enter();
-	if (!xfer->done) {
-		if (pipe->device->bus->use_polling)
-			panic("usbd_transfer: not done");
-		tsleep(xfer, 0, "usbsyn", 0);
+	while (!xfer->done) {
+		if (pipe->device->bus->use_polling) {
+			usbd_dopoll(pipe->iface);
+			kprintf("warning: usbd_transfer: not done\n");
+		}
+		tsleep(xfer, 0, "usbsyn", hz);
 	}
 	crit_exit();
 	return (xfer->status);