[BLUETOOTH]: Always send explicit hci_ll wake-up acks.

In the (rare) event of simultaneous mutual wake up requests,
do send the chip an explicit wake-up ack. This is required
for Texas Instruments's BRF6350 chip.

Signed-off-by: Ohad Ben-Cohen <ohad@bencohen.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 9 deletions

diff --git a/drivers/bluetooth/hci_ll.c b/drivers/bluetooth/hci_ll.c
index 8c3e62a17b4..b91d45a41b2 100644
--- a/drivers/bluetooth/hci_ll.c
+++ b/drivers/bluetooth/hci_ll.c
@@ -204,6 +204,19 @@ static void ll_device_want_to_wakeup(struct hci_uart *hu)
         spin_lock_irqsave(&ll->hcill_lock, flags);
 
         switch (ll->hcill_state) {
+        case HCILL_ASLEEP_TO_AWAKE:
+                /*
+                 * This state means that both the host and the BRF chip
+                 * have simultaneously sent a wake-up-indication packet.
+                 * Traditionaly, in this case, receiving a wake-up-indication
+                 * was enough and an additional wake-up-ack wasn't needed.
+                 * This has changed with the BRF6350, which does require an
+                 * explicit wake-up-ack. Other BRF versions, which do not
+                 * require an explicit ack here, do accept it, thus it is
+                 * perfectly safe to always send one.
+                 */
+                BT_DBG("dual wake-up-indication");
+                /* deliberate fall-through - do not add break */
         case HCILL_ASLEEP:
                 /* acknowledge device wake up */
                 if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
@@ -211,16 +224,8 @@ static void ll_device_want_to_wakeup(struct hci_uart *hu)
                         goto out;
                 }
                 break;
-        case HCILL_ASLEEP_TO_AWAKE:
-                /*
-                 * this state means that a wake-up-indication
-                 * is already on its way to the device,
-                 * and will serve as the required wake-up-ack
-                 */
-                BT_DBG("dual wake-up-indication");
-                break;
         default:
-                /* any other state are illegal */
+                /* any other state is illegal */
                 BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
                 break;
         }