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* [PATCH 0/2] Bluetooth: hci_event: Fix connection state issues during suspend/resume
@ 2025-08-12 14:10 Ludovico de Nittis
  2025-08-12 14:10 ` [PATCH 1/2] Bluetooth: hci_event: Treat UNKNOWN_CONN_ID on disconnect as success Ludovico de Nittis
  2025-08-12 14:10 ` [PATCH 2/2] Bluetooth: hci_event: Mark connection as closed during suspend disconnect Ludovico de Nittis
  0 siblings, 2 replies; 9+ messages in thread
From: Ludovico de Nittis @ 2025-08-12 14:10 UTC (permalink / raw)
  To: linux-bluetooth; +Cc: Ludovico de Nittis

This patch series addresses connection state synchronization issues
between the Bluetooth controller and kernel during suspend/resume cycles.

The problem seems to be visible when using devices that very quickly try
to send multiple reconnect events without waiting enough for the host
to fully resume from suspend.

Fixes the issues reported in https://github.com/bluez/bluez/issues/1226.

Ludovico de Nittis (2):
  Bluetooth: hci_event: Treat UNKNOWN_CONN_ID on disconnect as success
  Bluetooth: hci_event: Mark connection as closed during suspend
    disconnect

 net/bluetooth/hci_event.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

-- 
2.50.1


^ permalink raw reply	[flat|nested] 9+ messages in thread
* [PATCH v2 1/2] Bluetooth: hci_event: Treat UNKNOWN_CONN_ID on disconnect as success
@ 2025-08-12 15:55 Ludovico de Nittis
  2025-08-12 16:40 ` Bluetooth: hci_event: Fix connection state issues during suspend/resume bluez.test.bot
  0 siblings, 1 reply; 9+ messages in thread
From: Ludovico de Nittis @ 2025-08-12 15:55 UTC (permalink / raw)
  To: linux-bluetooth; +Cc: Ludovico de Nittis

When the host sends an HCI_OP_DISCONNECT command, the controller may
respond with the status HCI_ERROR_UNKNOWN_CONN_ID (0x02). 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.

This is a btmon snippet that shows the issue:
```
> ACL Data RX: Handle 3 flags 0x02 dlen 12
      L2CAP: Disconnection Request (0x06) ident 5 len 4
        Destination CID: 65
        Source CID: 72
< ACL Data TX: Handle 3 flags 0x00 dlen 12
      L2CAP: Disconnection Response (0x07) ident 5 len 4
        Destination CID: 65
        Source CID: 72
> ACL Data RX: Handle 3 flags 0x02 dlen 12
      L2CAP: Disconnection Request (0x06) ident 6 len 4
        Destination CID: 64
        Source CID: 71
< ACL Data TX: Handle 3 flags 0x00 dlen 12
      L2CAP: Disconnection Response (0x07) ident 6 len 4
        Destination CID: 64
        Source CID: 71
< HCI Command: Set Event Mask (0x03|0x0001) plen 8
        Mask: 0x3dbff807fffbffff
          Inquiry Complete
          Inquiry Result
          Connection Complete
          Connection Request
          Disconnection Complete
          Authentication Complete
[...]
< HCI Command: Disconnect (0x01|0x0006) plen 3
        Handle: 3 Address: 78:20:A5:4A:DF:28 (Nintendo Co.,Ltd)
        Reason: Remote User Terminated Connection (0x13)
> HCI Event: Command Status (0x0f) plen 4
      Disconnect (0x01|0x0006) ncmd 1
        Status: Unknown Connection Identifier (0x02)
```

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.

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);
 
-- 
2.50.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2025-08-12 16:40 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-08-12 14:10 [PATCH 0/2] Bluetooth: hci_event: Fix connection state issues during suspend/resume Ludovico de Nittis
2025-08-12 14:10 ` [PATCH 1/2] Bluetooth: hci_event: Treat UNKNOWN_CONN_ID on disconnect as success Ludovico de Nittis
2025-08-12 14:36   ` Bluetooth: hci_event: Fix connection state issues during suspend/resume bluez.test.bot
2025-08-12 15:20   ` [PATCH 1/2] Bluetooth: hci_event: Treat UNKNOWN_CONN_ID on disconnect as success Paul Menzel
2025-08-12 15:57     ` Ludovico de Nittis
2025-08-12 14:10 ` [PATCH 2/2] Bluetooth: hci_event: Mark connection as closed during suspend disconnect Ludovico de Nittis
2025-08-12 14:41   ` Luiz Augusto von Dentz
2025-08-12 14:52     ` Ludovico de Nittis
  -- strict thread matches above, loose matches on Subject: below --
2025-08-12 15:55 [PATCH v2 1/2] Bluetooth: hci_event: Treat UNKNOWN_CONN_ID on disconnect as success Ludovico de Nittis
2025-08-12 16:40 ` Bluetooth: hci_event: Fix connection state issues during suspend/resume bluez.test.bot

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