Start up a test on your driver and simultaneously run:
# uadmin 3 8
You can also test Suspend/Resume by generating I/O to your device, and then pressing the top-right button on the keyboard to suspend the machine. Then resume the machine; there should be no panics, error messages, or data corruption.
If you have access to a server system that supports Dynamic Reconfiguration, you may also want to test your driver on this configuration.