There needs to be a wmb() barrier between the write to the cycle bit in the first TRB and the write to the doorbell register.
Since it isn't needed in the other places the doobell is rung (because the ring contents haven't been changed) add it to giveback_first_trb() rather than somewhere later. Signed-off-by: David Laight <[email protected]> --- This patch will only apply cleanly if my earlier patch that affects the previous line has also been applied. drivers/usb/host/xhci-ring.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 35dfed0..8bce4c3 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -3136,6 +3136,7 @@ static void giveback_first_trb(struct xhci_hcd *xhci, int slot_id, */ wmb(); start_trb->field[3] ^= cpu_to_le32(TRB_CYCLE); + wmb(); xhci_ring_ep_doorbell(xhci, slot_id, ep_index, stream_id); } -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
