This commit introduced asserts from usb.c and hangs (keyboard non-responding, but machine does not reboot automatically)

commit f6604627ff71d42bb63a3d81c2986a9d296d55cb
Author: Michael Brown <mcb30@ipxe.org>
Date:   Wed May 6 16:38:28 2015 +0100

    [usb] Detect missed disconnections

    The USB core will currently fail to detect disconnections if a new
    device has attached by the time the port is examined in
    usb_hotplug().

    Fix by recording the fact that a disconnection has taken place
    whenever the "connection status changed" (CSC) bit is observed to be
    set.  (Whether the change represents a disconnection or a
    reconnection, it indicates that the port has experienced some time of
    being disconnected.)

    Note that the time at which a disconnection can be detected varies by
    hub type.  In particular: root hubs can observe the CSC bit when
    polling, and so will record the disconnection before calling
    usb_port_changed(), but USB hubs read the port status (and hence the
    CSC bit) only during the call to hub_speed(), long after the call to
    usb_port_changed().

    Signed-off-by: Michael Brown <mcb30@ipxe.org>

:040000 040000 ec1438f8203a90092932ed1fef4880b90f3c94ad 0be35594b2890d5c4aceb4c7f5b3d56ad990c0e0 M      src


This commit has asserts AND also reboots machine automatically

commit b3de9664c7b7d4878d3dcd5a3c62a8e0155d5e89
Author: Michael Brown <mcb30@ipxe.org>
Date:   Fri May 8 15:33:18 2015 +0100

    [ehci] Poll child companion controllers after disowning port

    Signed-off-by: Michael Brown <mcb30@ipxe.org>

:040000 040000 2ecae7bc4db8b08252039e3edbae0d7bb0b162df b843c4f1111849c207b7263a35cf65463654c9e5 M      src