diff -ruN ata/ata-queue.c ata.fixed/ata-queue.c
--- ata/ata-queue.c	Fri Sep 23 20:06:10 2005
+++ ata.fixed/ata-queue.c	Wed Dec 14 18:52:58 2005
@@ -428,11 +430,14 @@
 	if (composite->wr_depend &&
 	    (composite->rd_done & composite->wr_depend)==composite->wr_depend &&
 	    (composite->wr_needed & (~composite->wr_done))) {
-	    index = ((composite->wr_needed & (~composite->wr_done))) - 1;
+	    index = (composite->wr_needed & (~composite->wr_done));
 	}
 	mtx_unlock(&composite->lock);
-	if (index)
+	if (index) {
+	    /* should be really bitshift */
+	    index = index - 1;
 	    ata_start(device_get_parent(composite->request[index]->dev));
+	}
     }
 
     /* get results back to the initiator */