TCP Spurious Retransmission when both BT and WIFI are enabled

[axellin]

Hi,
I test with master tree (v3.3-dev-270-g6f8e2b018).
When BT and Wifi are both enabled, it's easy to observe "TCP Spurious Retransmission" issue.
In my case, I only use BLE by calling esp_ble_gap_start_scanning().
The scan_interval=0x50 and scan_widow=0x30 in my setting.

If I comment out the esp_ble_gap_start_scanning() call, I don't observe the issue.
So I guess this might be related to BT+WiFi co-exist issue?

[chegewara]

Hi,
try SW coexistnce option in menuconfig with wifi priority. ble should not lose too much but it will change your wifi behavior a lot, at least i experienced it in my test app. I even could set scan interval and windows with the same value and wifi didnt complain about it.

[axellin]

Set SW coexistnce with wifi priority reduce the chance or TCP Spurious Retransmission, but it still can happen.
Comment out esp_ble_gap_start_scanning() then the TCP Spurious Retransmission never happen.
I do believe there are some issues with bt+wifi coexist...