enable driver internal trace

configname: CONFIG_SCSI_IBMVFC_TRACE

Linux Kernel Configuration
└─>Device Drivers
└─>SCSI device support
└─>SCSI low-level drivers
└─>enable driver internal trace
In linux kernel since version 2.6.27 (release Date: 2008-10-09)  
If you say Y here, the driver will trace all commands issued
to the adapter. Performance impact is minimal. Trace can be
dumped using /sys/class/scsi_host/hostXX/trace.