A method, system, and computer product for aiding in the debugging of an
I/O failure. When an I/O failure is detected on a RIO drawer, a data
processing system uses the bulk power controller to provide an alternate
path, rather than using the existing RIO links, to access registers on
the I/O drawers. The system logs onto the bulk power controller, which
provides a communications path between the data processing system and the
RIO drawer. The communications path allows the data processing system to
read the chip registers on the I/O drawer. The data processing system
captures I/O failure information in the I/O drawer using the
communications path, wherein the I/O failure information is used to debug
the I/O failure.