Patent ID: 6862642
Filing Date: 2005-03-01
Classification: G06F

Abstract:
1. A method for resetting bus segments to clear bus hang in an I/O subsystem having a plurality of bus segments, each bus segment having a set of devices and a bus that is coupled to the set of devices, the I/O subsystem having at least one expander, each expander being arranged to couple a pair of buses for propagating communication signals, a first of the bus segments being coupled by a first one of the expanders only to a second of the bus segments, the method comprising the operations of: a) asserting a first reset signal on only the first bus segment in a manner by which the first reset signal is normally transmitted through the first expander to the second bus segment; b) in response to the first reset signal asserted on the first bus segment, resetting the first expander coupled to the first bus segment and resetting each device in the first bus segment and establishing a first reset isolation mode of the first expander to perform reset signal isolation such that the first reset signal is not propagated through the first expander to the second bus segment; c) operating the first expander coupled to the first bus segment for: