The target drivers use scsi_ifsetcap(9F) to set the capabilities of the host adapter driver. A cap is a name-value pair whose name is a null terminated character string and whose value is an integer. The current value of a capability can be retrieved using scsi_ifgetcap(9F). scsi_ifsetcap(9F) allows capabilities to be set for all targets on the bus.
In general, however, setting capabilities of targets that are not owned by the target driver is not recommended and is not universally supported by HBA drivers. Some capabilities (such as disconnect and synchronous) may be set by default by the HBA driver but others may need to be explicitly set by the target driver (wide-xfer or tagged-queing, for example).