--- src/sys/bus/cam/cam_xpt.c	2007/11/28 22:11:02	1.46
+++ src/sys/bus/cam/cam_xpt.c	2007/11/28 22:21:48	1.47
@@ -5463,7 +5463,17 @@ probestart(struct cam_periph *periph, un
 		if (softc->action == PROBE_INQUIRY)
 			inquiry_len = SHORT_INQUIRY_LENGTH;
 		else
-			inquiry_len = inq_buf->additional_length + 5;
+			inquiry_len = inq_buf->additional_length
+				    + offsetof(struct scsi_inquiry_data,
+                                               additional_length) + 1;
+
+		/*
+		 * Some parallel SCSI devices fail to send an
+		 * ignore wide residue message when dealing with
+		 * odd length inquiry requests.  Round up to be
+		 * safe.
+		 */
+		inquiry_len = roundup2(inquiry_len, 2);
 	
 		scsi_inquiry(csio,
 			     /*retries*/4,