xhci: Fix isoc TD encoding.

An isochronous TD is comprised of one isochronous TRB chained to zero or
more normal TRBs.  Only the isoc TRB has the TBC and TLBPC fields.  The
normal TRBs must set those fields to zeroes.  The code was setting the
TBC and TLBPC fields for both isoc and normal TRBs.  Fix this.

This should be backported to stable kernels as old as 3.0, that contain
the commit b61d378f2da41c748aba6ca19d77e1e1c02bcea5 " xhci 1.0: Set
transfer burst last packet count field."

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 59fb5c6..d1ff133 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3664,9 +3664,11 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                td = urb_priv->td[i];
                for (j = 0; j < trbs_per_td; j++) {
                        u32 remainder = 0;
-                       field = TRB_TBC(burst_count) | TRB_TLBPC(residue);
+                       field = 0;
 
                        if (first_trb) {
+                               field = TRB_TBC(burst_count) |
+                                       TRB_TLBPC(residue);
                                /* Queue the isoc TRB */
                                field |= TRB_TYPE(TRB_ISOC);
                                /* Assume URB_ISO_ASAP is set */