Timeout on LE Create Connection which call LE Create Connection Cancel

[francois-fiveco]

We have a BLE device with an advertisement interval of 5 seconds.
As of Bluez version 5.69, an HCI ‘LE Create Connection Cancel’ command is called approximately 4 seconds after the HCI ‘LE Create Connection’ command if the connection was not successful.
With version 5.68 or older, the HCI command ‘LE Create Connection Cancel’ does not seem to be called or is called with a much longer timeout.

Is it possible to change this timeout?
If so, where?

Trying to connect :

sudo gatttool -b D4:9F:EA:97:2D:AB -I -t random
[D4:9F:EA:97:2D:AB][LE]> connect
Attempting to connect to D4:9F:EA:97:2D:AB
Error: connect to D4:9F:EA:97:2D:AB: Connection timed out (110)

Monitor :

sudo btmon
Bluetooth monitor ver 5.69
btmon[1007]: = Note: Linux version 6.6.51+rpt-rpi-v8 (aarch64)                                                                                                                                                                      0.256526
btmon[1007]: = Note: Bluetooth subsystem version 2.22                                                                                                                                                                               0.256535
= New Index: D8:3A:DD:83:29:6B (Primary,UART,hci0)                                                                                                                                                                           [hci0] 0.256539
= Open Index: D8:3A:DD:83:29:6B                                                                                                                                                                                              [hci0] 0.256541
= Index Info: D8:3A:DD:83:29:6B (Cypress Semiconductor)                                                                                                                                                                      [hci0] 0.256543
bluetoothd[538]: @ MGMT Open: bluetoothd (privileged) version 1.22                                                                                                                                                         {0x0001} 0.256548
< HCI Command: LE Set Scan Parameters (0x08|0x000b) plen 7                                                                                                                                                               #1 [hci0] 22.009787
        Type: Passive (0x00)
        Interval: 60.000 msec (0x0060)
        Window: 60.000 msec (0x0060)
        Own address type: Public (0x00)
        Filter policy: Ignore not in accept list (0x01)
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                                                                              #2 [hci0] 22.010137
      LE Set Scan Parameters (0x08|0x000b) ncmd 1
        Status: Success (0x00)
< HCI Command: LE Set Scan Enable (0x08|0x000c) plen 2                                                                                                                                                                   #3 [hci0] 22.010212
        Scanning: Enabled (0x01)
        Filter duplicates: Enabled (0x01)
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                                                                              #4 [hci0] 22.010600
      LE Set Scan Enable (0x08|0x000c) ncmd 1
        Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 36                                                                                                                                                                                #5 [hci0] 22.750887
      LE Advertising Report (0x02)
        Num reports: 1
        Event type: Connectable undirected - ADV_IND (0x00)
        Address type: Random (0x01)
        Address: D4:9F:EA:97:2D:AB (Static)
        Data length: 24
        Flags: 0x06
          LE General Discoverable Mode
          BR/EDR Not Supported
        Company: FiveCo Sarl (1806)
          Data: 30cb0034000a034a091b0f1d0c12ab2dcc
        RSSI: -80 dBm (0xb0)
< HCI Command: LE Set Scan Enable (0x08|0x000c) plen 2                                                                                                                                                                   #6 [hci0] 22.750964
        Scanning: Disabled (0x00)
        Filter duplicates: Disabled (0x00)
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                                                                              #7 [hci0] 22.752373
      LE Set Scan Enable (0x08|0x000c) ncmd 1
        Status: Success (0x00)
< HCI Command: LE Create Connection (0x08|0x000d) plen 25                                                                                                                                                                #8 [hci0] 22.752444
        Scan interval: 60.000 msec (0x0060)
        Scan window: 60.000 msec (0x0060)
        Filter policy: Accept list is not used (0x00)
        Peer address type: Random (0x01)
        Peer address: D4:9F:EA:97:2D:AB (Static)
        Own address type: Public (0x00)
        Min connection interval: 7.50 msec (0x0006)
        Max connection interval: 100.00 msec (0x0050)
        Connection latency: 1 (0x0001)
        Supervision timeout: 5000 msec (0x01f4)
        Min connection length: 0.000 msec (0x0000)
        Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4                                                                                                                                                                                #9 [hci0] 22.753024
      LE Create Connection (0x08|0x000d) ncmd 1
        Status: Success (0x00)
< HCI Command: LE Create Connection Cancel (0x08|0x000e) plen 0                                                                                                                                                         #10 [hci0] 26.822839
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                                                                             #11 [hci0] 26.825684
      LE Create Connection Cancel (0x08|0x000e) ncmd 1
        Status: Success (0x00)
@ MGMT Event: Connect Failed (0x000d) plen 8                                                                                                                                                                       {0x0001} [hci0] 26.825755
        LE Address: D4:9F:EA:97:2D:AB (Static)
        Status: Timeout (0x08)
> HCI Event: LE Meta Event (0x3e) plen 19                                                                                                                                                                               #12 [hci0] 26.825825
      LE Connection Complete (0x01)
        Status: Unknown Connection Identifier (0x02)
        Handle: 64
        Role: Central (0x00)
        Peer address type: Random (0x01)
        Peer address: D4:9F:EA:97:2D:AB (Static)
        Connection interval: 97.50 msec (0x004e)
        Connection latency: 1 (0x0001)
        Supervision timeout: 5000 msec (0x01f4)
        Central clock accuracy: 0x00

[francois-fiveco]

The problem arose from the "Autoconnecttimeout" parameter that we had set to 30000 in the ‘main.conf’ file.
A bug, which has been corrected as of version 5.69, in the ‘parse_config_int’ function in the ‘main.c’ file did not prevent us from writing a value greater than the maximum defined for this 0x4000 parameter (16384).
By writing a value of 16380 for the Autoconnecttimeout parameter in the ‘main.conf’ file, our devices connect much more easily.