Re: [PATCH 1/2] Bluetooth: hci_event: Treat UNKNOWN_CONN_ID on disconnect as success

[Ludovico de Nittis <ludovico.denittis@collabora.com>]

Hi Paul,

On 8/12/25 5:20 PM, Paul Menzel wrote:
> Dear Ludovico,
>
>
> Thank you for your patch.
>
> Am 12.08.25 um 16:10 schrieb Ludovico de Nittis:
>> When the host sends an HCI_OP_DISCONNECT command, the controller may
>> respond with the status HCI_ERROR_UNKNOWN_CONN_ID. E.g. this can happen
>> on resume from suspend, if the link was terminated by the remote device
>> before the event mask was correctly set.
>>
>> Currently, the hci_cs_disconnect function treats any non-zero status
>> as a command failure. This can be misleading because the connection is
>> indeed being terminated and the controller is confirming that is has no
>> knowledge of that connection handle. Meaning that the initial request of
>> disconnecting a device should be treated as done.
>>
>> With this change we allow the function to proceed, following the success
>> path, which correctly calls `mgmt_device_disconnected` and ensures a
>> consistent state.
>
> Although part of your issue referenced below, I’d love to see the 
> reproducer in the commit message, should you resend.

Sure, in the v2 I added the btmon snippet in the commit message.

>> Link: https://github.com/bluez/bluez/issues/1226
>> Signed-off-by: Ludovico de Nittis <ludovico.denittis@collabora.com>
>> ---
>>   net/bluetooth/hci_event.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
>> index fe7cdd67a..6c67dfa13 100644
>> --- a/net/bluetooth/hci_event.c
>> +++ b/net/bluetooth/hci_event.c
>> @@ -2703,7 +2703,7 @@ static void hci_cs_disconnect(struct hci_dev 
>> *hdev, u8 status)
>>       if (!conn)
>>           goto unlock;
>>   -    if (status) {
>> +    if (status && status != HCI_ERROR_UNKNOWN_CONN_ID) {
>>           mgmt_disconnect_failed(hdev, &conn->dst, conn->type,
>>                          conn->dst_type, status);
>
> Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
>
>
> Kind regards,
>
> Paul