IOPanic ans assert not working ?

I had no response from darwin driver list s olet's try here... I'm at the point in my driver that I want to make sure I get proper assertions and IOPanic. I tried both in my code and defined MACH_ASSERT (to enable assert(false);). When I load my kernel, it just freeze my computer. No messages, nothing in the log no panic... Just a plain system freeze. I also tried IOPanic with a string message and it does the same freeze. No message, no stack trace. Do I have to do something special to get a message. Debugging is gonna be hard if I can't assert! Thanks Francis