USB_TASKQ_HC
usb_add_task(dev, &xfer->ux_aborttask, USB_TASKQ_HC);
USB_TASKQ_HC, xfer->ux_bus->ub_lock);
usb_rem_task_wait(pipe->up_dev, &xp->xp_async_task, USB_TASKQ_HC,
usb_add_task(pipe->up_dev, &xp->xp_async_task, USB_TASKQ_HC);