IB/qib: Don't mark VL15 bufs as WC to avoid a rare 7322 chip problem

Don't set write combining via PAT on the VL15 buffers to avoid a rare
problem with unaligned writes from interrupt-flushed store buffers.

Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/qib/qib_tx.c

@@ -340,9 +340,13 @@ rescan:
 		if (i < dd->piobcnt2k)
 			buf = (u32 __iomem *)(dd->pio2kbase +
 				i * dd->palign);
-		else
+		else if (i < dd->piobcnt2k + dd->piobcnt4k || !dd->piovl15base)
 			buf = (u32 __iomem *)(dd->pio4kbase +
 				(i - dd->piobcnt2k) * dd->align4k);
+		else
+			buf = (u32 __iomem *)(dd->piovl15base +
+				(i - (dd->piobcnt2k + dd->piobcnt4k)) *
+				dd->align4k);
 		if (pbufnum)
 			*pbufnum = i;
 		dd->upd_pio_shadow = 0;