From: Chethan T N <chethan.tumkur.narayan@xxxxxxxxx>
Observed race condition during controller recovery mechanism
resulting the controller not responding to the reset command.
To avoid such race condition need a delay of 2ms soon after the
USB re-enumeration and before sending the Reset command which shall
allow controller to completely recover and process the Reset command.
BUG=b:64035404
TEST=Magic tethering, P0 and P1 santiy test cases, kernel-boot log
Signed-off-by: Chethan T N <chethan.tumkur.narayan@xxxxxxxxx>
Signed-off-by: Amit K Bag <amit.k.bag@xxxxxxxxx>
---
drivers/bluetooth/btusb.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index f73a27ea28cc..c7fce9c11889 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -1743,6 +1743,15 @@ static int btusb_setup_intel(struct hci_dev *hdev)
BT_DBG("%s", hdev->name);
+ /* Observed race condition during controller recovery mechanism
+ * resulting the controller not responding to the reset command.
+ *
+ * To avoid such race condition need a delay of 2ms soon after the
+ * USB re-enumeration and before sending the Reset command which shall
+ * allow controller to completely recover and process the Reset command.
+ */
+ mdelay(2);
+
/* The controller has a bug with the first HCI command sent to it
* returning number of completed commands as zero. This would stall the
* command processing in the Bluetooth core.
--
2.7.4
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