Writing Device Drivers

SCSI Options

SCSA defines a global variable, scsi_options, which can be used for debug and control. The defined bits in scsi_options can be found in the file <sys/scsi/conf/autoconf.h>. Table 14-2 shows their meanings when set.

Table 14-2 SCSA Options


Option	Description
`SCSI_OPTIONS_DR`	Enables global disconnect/reconnect.
`SCSI_OPTIONS_SYNC`	Enables global synchronous transfer capability.
`SCSI_OPTIONS_LINK`	Enables global link support.
`SCSI_OPTIONS_PARITY`	Enables global parity support.
`SCSI_OPTIONS_TAG`	Enables global tagged queuing support.
`SCSI_OPTIONS_FAST`	Enables global FAST SCSI support: 10MB/sec transfers, as opposed to 5 MB/sec.
`SCSI_OPTIONS_FAST20`	Enables global FAST20 SCSI support: 20MB/sec transfers.
`SCSI_OPTIONS_FAST40`	Enables global FAST40 SCSI support: 40MB/sec transfers.
`SCSI_OPTIONS_FAST80`	Enables global FAST80 SCSI support: 80MB/sec transfers.
`SCSI_OPTIONS_WIDE`	Enables global WIDE SCSI.

Note -

The setting of scsi_options affects all host adapter and target drivers present on the system (as opposed to scsi_ifsetcap(9F)). Refer to scsi_hba_attach(9F) for information on controlling these options for a particular host adapter.