Don't make things more complex than necessary. From the driver perspective, there are two types of property repositories:
1. driver.conf, accessed via ddi_prop_get_* interfaces. 2. dladm properties, accessed via mac_prop_get_* interfaces. They do NOT overlap. When one changes, another does not change. Current design does not provide driver.conf/dladm syncing capabilities - and I think it never should. The driver can access property repositories in either order. In what order the driver applies properties is entirely up to the driver. If dladm repository contains no default_mtu for the link in question, naturally, mac_prop_get_* will not return any value. -Artem
