+	if((uninorth_rev >= 0x30) && (uninorth_rev <= 0x33)) {
+		/*
+		 * We need to to set REQ_DEPTH to 7 for U3 versions 1.0, 2.1,
+		 * 2.2 and 2.3, Darwin do so.
+		 */
+		command |= (7 << AGPSTAT_RQ_DEPTH_SHIFT);
+	}
 

Some revs of U3 (3.x) do have some high bits sets in the version
register, you should probably mask it with 0x3f ... Though on the other
hand, I don't know if revisions prior to 3.x were ever used on
production...

Ben.