[PATCH] Bluetooth: Add SCO fallback for invalid LMP parameters error

From: Hsin-Yu Chao
Date: Fri May 15 2020 - 05:27:12 EST


From: Hsin-Yu Chao <hychao@xxxxxxxxxxxx>

Bluetooth PTS test case HFP/AG/ACC/BI-12-I accepts SCO connection
with invalid parameter at the first SCO request expecting AG to
attempt another SCO request with the use of "safe settings" for
given codec, base on section 5.7.1.2 of HFP 1.7 specification.

This patch addresses it by adding "Invalid LMP Parameters" (0x1e)
to the SCO fallback case. Verified with below log:

< HCI Command: Setup Synchronous Connection (0x01|0x0028) plen 17
Handle: 256
Transmit bandwidth: 8000
Receive bandwidth: 8000
Max latency: 13
Setting: 0x0003
Input Coding: Linear
Input Data Format: 1's complement
Input Sample Size: 8-bit
# of bits padding at MSB: 0
Air Coding Format: Transparent Data
Retransmission effort: Optimize for link quality (0x02)
Packet type: 0x0380
3-EV3 may not be used
2-EV5 may not be used
3-EV5 may not be used
> HCI Event: Command Status (0x0f) plen 4
Setup Synchronous Connection (0x01|0x0028) ncmd 1
Status: Success (0x00)
> HCI Event: Number of Completed Packets (0x13) plen 5
Num handles: 1
Handle: 256
Count: 1
> HCI Event: Max Slots Change (0x1b) plen 3
Handle: 256
Max slots: 1
> HCI Event: Synchronous Connect Complete (0x2c) plen 17
Status: Invalid LMP Parameters / Invalid LL Parameters (0x1e)
Handle: 0
Address: 00:1B:DC:F2:21:59 (OUI 00-1B-DC)
Link type: eSCO (0x02)
Transmission interval: 0x00
Retransmission window: 0x02
RX packet length: 0
TX packet length: 0
Air mode: Transparent (0x03)
< HCI Command: Setup Synchronous Connection (0x01|0x0028) plen 17
Handle: 256
Transmit bandwidth: 8000
Receive bandwidth: 8000
Max latency: 8
Setting: 0x0003
Input Coding: Linear
Input Data Format: 1's complement
Input Sample Size: 8-bit
# of bits padding at MSB: 0
Air Coding Format: Transparent Data
Retransmission effort: Optimize for link quality (0x02)
Packet type: 0x03c8
EV3 may be used
2-EV3 may not be used
3-EV3 may not be used
2-EV5 may not be used
3-EV5 may not be used
> HCI Event: Command Status (0x0f) plen 4
Setup Synchronous Connection (0x01|0x0028) ncmd 1
Status: Success (0x00)
> HCI Event: Max Slots Change (0x1b) plen 3
Handle: 256
Max slots: 5
> HCI Event: Max Slots Change (0x1b) plen 3
Handle: 256
Max slots: 1
> HCI Event: Synchronous Connect Complete (0x2c) plen 17
Status: Success (0x00)
Handle: 257
Address: 00:1B:DC:F2:21:59 (OUI 00-1B-DC)
Link type: eSCO (0x02)
Transmission interval: 0x06
Retransmission window: 0x04
RX packet length: 30
TX packet length: 30
Air mode: Transparent (0x03)

Signed-off-by: Hsin-Yu Chao <hychao@xxxxxxxxxxxx>
---
net/bluetooth/hci_event.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 73aabca0064b7..f024b3d57a1c7 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4337,6 +4337,7 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
case 0x11: /* Unsupported Feature or Parameter Value */
case 0x1c: /* SCO interval rejected */
case 0x1a: /* Unsupported Remote Feature */
+ case 0x1e: /* Invalid LMP Parameters */
case 0x1f: /* Unspecified error */
case 0x20: /* Unsupported LMP Parameter value */
if (conn->out) {
--
2.24.1