注册设备 ID

通常，驱动程序在其 attach(9E) 处理程序中初始化和注册设备 ID。如上所述，驱动程序负责注册永久设备 ID。同时，驱动程序可能需要处理可直接提供唯一 ID (WWN) 的设备和向稳定存储器写入及从稳定存储器读取虚构 ID 的设备。

注册设备提供的 ID

如果设备可以为驱动程序提供唯一的标识符，则驱动程序可以直接使用此标识符初始化设备 ID 并使用 Oracle Solaris DDI 注册此 ID。

/*
 * The device provides a guaranteed unique identifier,
 * in this case a SCSI3-WWN.  The WWN for the device has been
 * stored in the device's soft state.
 */
if (ddi_devid_init(dip, DEVID_SCSI3_WWN, un->un_wwn_len, un->un_wwn,
    &un->un_devid) != DDI_SUCCESS)
    return (DDI_FAILURE);

(void) ddi_devid_register(dip, un->un_devid);

注册虚构 ID

驱动程序还可能为不直接提供唯一 ID 的设备注册设备 ID。注册这些 ID 需要设备能够存储并检索保留区中的少量数据。随后，驱动程序可创建虚构设备 ID 并将其写入保留区中。

/*
 * the device doesn't supply a unique ID, attempt to read
 * a fabricated ID from the device's reserved data.
 */
if (xxx_read_deviceid(un, &devid_buf) == XXX_OK) {
    if (ddi_devid_valid(devid_buf) == DDI_SUCCESS) {
        devid_sz = ddi_devi_sizeof(devid_buf);
        un->un_devid = kmem_alloc(devid_sz, KM_SLEEP);
        bcopy(devid_buf, un->un_devid, devid_sz);
        ddi_devid_register(dip, un->un_devid);
        return (XXX_OK);
    }
}
/*
 * we failed to read a valid device ID from the device
 * fabricate an ID, store it on the device, and register
 * it with the DDI
 */
if (ddi_devid_init(dip, DEVID_FAB, 0, NULL, &un->un_devid)
    == DDI_FAILURE) {
    return (XXX_FAILURE);
}
if (xxx_write_deviceid(un) != XXX_OK) {
    ddi_devid_free(un->un_devid);
    un->un_devid = NULL;
    return (XXX_FAILURE);
}
ddi_devid_register(dip, un->un_devid);
return (XXX_OK);