KB1005576 explains how to enable or disable verbose logging on QLogic and Emulex Host Bus Adapters. With ESXi 5.5 and its Native Device Driver Architecture the option has been slightly changed, but is still available. This post explains how to enable verbose logging on QLogic and Emulex HBAs in ESXi 5.5.
The new native drivers and their predecessor are:
Emulex FC: lpfc (replaces lpfc820)
QLogic FC: qlnativefc (replaces qla2xxx)