BlueZ 5.19: BLE HoG device reconnect issues

[Petri Gynther <pgynther@google.com>]

With BlueZ 5.19 stack and BLE HoG remote controls, I'm seeing 3
different issues when trying to reconnect a previously paired BLE HoG
remote control:

Full log:
[72241.012] bluez: bluetoothd[29263]:
src/adapter.c:discovering_callback() hci0 type 6 discovering 1
[72251.269] bluez: bluetoothd[29263]:
src/adapter.c:device_found_callback() hci0 addr 88:33:14:E6:XX:XX,
rssi -81 flags 0x0000 eir_len 16
[72251.270] bluez: bluetoothd[29263]: src/device.c:device_set_legacy() legacy 0
[72251.270] bluez: bluetoothd[29263]: src/adapter.c:stop_passive_scanning()
[72251.270] bluez: bluetoothd[29263]:
src/adapter.c:discovering_callback() hci0 type 6 discovering 0
[72251.270] bluez: bluetoothd[29263]:
src/adapter.c:trigger_passive_scanning()
[72251.270] bluez: bluetoothd[29263]:
src/adapter.c:stop_passive_scanning_complete() status 0x0b (Rejected)
[72251.270] bluez: bluetoothd[29263]: Stopping passive scanning failed: Rejected
[72255.015] bluez: bluetoothd[29263]:
src/adapter.c:passive_scanning_complete() status 0x00
[72255.015] bluez: bluetoothd[29263]:
src/adapter.c:discovering_callback() hci0 type 6 discovering 1
[72258.550] bluez: bluetoothd[29263]:
src/adapter.c:device_found_callback() hci0 addr 88:33:14:E6:XX:XX,
rssi -76 flags 0x0000 eir_len 16
[72258.551] bluez: bluetoothd[29263]: src/device.c:device_set_legacy() legacy 0
[72258.551] bluez: bluetoothd[29263]: src/adapter.c:stop_passive_scanning()
[72258.551] bluez: bluetoothd[29263]:
src/adapter.c:device_found_callback() hci0 addr CB:36:E5:F5:XX:XX,
rssi -82 flags 0x0000 eir_len 36
[72258.558] bluez: bluetoothd[29263]:
src/adapter.c:stop_passive_scanning_complete() status 0x00 (Success)
[72258.558] bluez: bluetoothd[29263]: src/device.c:device_connect_le()
Connection attempt to: 88:33:14:E6:XX:XX
[72258.558] bluez: bluetoothd[29263]:
src/adapter.c:discovering_callback() hci0 type 6 discovering 0
[72278.629] bluez: bluetoothd[29263]:
src/adapter.c:connect_failed_callback() hci0 88:33:14:E6:XX:XX status
2
[72278.629] bluez: bluetoothd[29263]: plugins/policy.c:conn_fail_cb() status 2
[72278.629] bluez: bluetoothd[29263]:
src/adapter.c:bonding_attempt_complete() hci0 bdaddr 88:33:14:E6:XX:XX
type 1 status 0x2
[72278.629] bluez: bluetoothd[29263]:
src/device.c:device_bonding_complete() bonding (nil) status 0x02
[72278.629] bluez: bluetoothd[29263]:
src/device.c:device_bonding_failed() status 2
[72278.629] bluez: bluetoothd[29263]: src/adapter.c:resume_discovery()
[72278.629] bluez: bluetoothd[29263]: src/device.c:att_connect_cb()
connect error: Transport endpoint is not connected (134)
[72278.629] bluez: bluetoothd[29263]: src/device.c:att_error_cb()
Enabling automatic connections
[72278.630] bluez: bluetoothd[29263]:
src/adapter.c:adapter_connect_list_add() ignoring already added device
/org/bluez/hci0/dev_88_33_14_E6_XX_XX

Issues 1 and 2:
[72251.270] bluez: bluetoothd[29263]: src/adapter.c:stop_passive_scanning()
[72251.270] bluez: bluetoothd[29263]:
src/adapter.c:discovering_callback() hci0 type 6 discovering 0
[72251.270] bluez: bluetoothd[29263]:
src/adapter.c:trigger_passive_scanning()
[72251.270] bluez: bluetoothd[29263]:
src/adapter.c:stop_passive_scanning_complete() status 0x0b (Rejected)
[72251.270] bluez: bluetoothd[29263]: Stopping passive scanning failed: Rejected

1) device_found_callback() -> update_found_devices() ->
stop_passive_scanning() needs to stop passive scanning because BlueZ
is about to connect to previously paired BLE device. But,
discovering_callback() doesn't take the pending BLE connection into
account and still calls trigger_passive_scanning() when it shouldn't.

2) stop_passive_scanning() can actually fail because passive scanning
was already stopped in kernel due to passive scan timer expiring. But,
stop_passive_scanning_complete() handles the Reject case as an error
and never attempts the pending BLE connection in that case.

Issue 3:
[72278.629] bluez: bluetoothd[29263]: src/device.c:att_connect_cb()
connect error: Transport endpoint is not connected (134)
[72278.629] bluez: bluetoothd[29263]: src/device.c:att_error_cb()
Enabling automatic connections
[72278.630] bluez: bluetoothd[29263]:
src/adapter.c:adapter_connect_list_add() ignoring already added device
/org/bluez/hci0/dev_88_33_14_E6_XX_XX

If there is an error connecting to BLE device, att_error_cb() adds the
failed device back to adapter connect list, but if it is already
there, no code actually calls trigger_passive_scanning(). So, from
this point on, no BLE device is ever going to reconnect back to BlueZ,
because the passive scanning is disabled and nothing will re-enable
it.


Here is my proposed diff for fixing these issues:
@@ -1228,7 +1228,7 @@ static void
stop_passive_scanning_complete(uint8_t status, uint16_t length,
        dev = adapter->connect_le;
        adapter->connect_le = NULL;

-       if (status != MGMT_STATUS_SUCCESS) {
+       if (status != MGMT_STATUS_SUCCESS && status != MGMT_STATUS_REJECTED) {
                error("Stopping passive scanning failed: %s",
                                                        mgmt_errstr(status));
                return;

@@ -1500,6 +1500,10 @@ static void discovering_callback(uint16_t
index, uint16_t length,
         * passive scanning attempt.
         */
        if (!adapter->discovery_list) {
+               if (adapter->connect_le) {
+                       DBG("LE connect pending, skip
trigger_passive_scanning");
+                       return;
+               }
                trigger_passive_scanning(adapter);
                return;
        }

@@ -3675,6 +3676,7 @@ static void att_error_cb(const GError *gerr,
gpointer user_data)
        if (device_get_auto_connect(device)) {
                DBG("Enabling automatic connections");
                adapter_connect_list_add(device->adapter, device);
+               trigger_passive_scanning(device->adapter);
        }
 }


Let me know if this looks good. I'll then e-mail proper patch for review.

-- Petri