Patent ID: 7673185

Claim:
A Serial-Attached-SCSI (SAS) expander, comprising: a plurality of SAS PHYs, each for coupling to a SAS cable for communication with a respective remote PHY; a memory, configured to store: a counter associated with each of said plurality of PHYs; and a table of PHY configuration settings, each entry in the table having different PHY configuration setting values; and a microprocessor, coupled to said memory and to said plurality of PHYs, configured to, for each of said plurality of PHYs: (a) configure the PHY with settings of an entry of the table; (b) clear the counter associated with the PHY; (c) operate the PHY to communicate with the remote PHY for a monitoring period, after configuring the PHY and clearing the counter; (d) increment the counter when the PHY detects a PHY event during the monitoring period, and otherwise decrement the counter; (e) repeat steps (c) and (d) unless the counter rises above a threshold; and (f) when the counter rises above the threshold, repeat steps (a) through (e), wherein the microprocessor performs step (a) with the settings of a different entry of the table.