Related to my previous vbl routine question. Looking at
	turn_vbl_function_off is appears it sets a vbl function's
	state to off BUT; it then goes in to a while loop soaking up CPU
	like nobody's business!! While spl3 is a low priority, shouldn't the
	routine sleep on the flag in the structure rather than waiting for
	a higher spl level call to turn_vbl_function_on() to flip the flag?!

	My kernel background regards tight spin loops in the kernel as evil,
	is this REALLY necessary?

		-Rob