this has not been tested yet, but i'm submitting anyway because of
potential server downtime.

Reference: /n/atom/patch/iasatasleepnou
Date: Mon Jul 14 19:20:55 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/fs/pc/iasata.c	Mon Jul 14 19:20:40 2014
+++ /sys/src/fs/pc/iasata.c	Mon Jul 14 19:20:41 2014
@@ -1565,6 +1565,7 @@
 	Drive *d;
 	vlong s;
 	char *lba;
+	Rendez r;
 	static int once;
 
 	if(once++ == 0)
@@ -1573,8 +1574,9 @@
 top:
 	d = iadev(dv);
 	if(d == nil || d->secsize == 0){
+		memset(&r, 0, sizeof r);
 		print("\t\t" "a%d.%d.%d not ready yet\n", dv->wren.ctrl, dv->wren.targ, dv->wren.lun);
-		waitmsec(500);
+		xtsleep(&r, no, nil, 500);
 		goto top;
 	}