A driver is loaded into memory when a device that the driver manages is accessed. A driver might be unloaded from memory when the driver is not being used. Normally, you do not need to load a driver into memory manually or unload a driver from memory manually.
To manually load a loadable module into memory, use the modload(1M) command.
While you are developing your driver, you might want to manually unload the driver and then update the driver. To manually unload a loadable module from memory, use the modunload(1M) command.