From 0b3725dbf61b51e7c663834811b3691157ae17d6 Mon Sep 17 00:00:00 2001 From: Pauli Virtanen Date: Sat, 9 Aug 2025 11:36:20 +0300 Subject: [PATCH] Bluetooth: hci_event: fix MTU for BN == 0 in CIS Established BN == 0x00 in CIS Established means no isochronous data for the corresponding direction (Core v6.1 pp. 2394). In this case SDU MTU should be 0. However, the specification does not say the Max_PDU_C_To_P or P_To_C are then zero. Intel AX210 in Framed CIS mode sets nonzero Max_PDU for direction with zero BN. This causes failure later when we try to LE Setup ISO Data Path for disabled direction, which is disallowed (Core v6.1 pp. 2750). Fix by setting SDU MTU to 0 if BN == 0. Fixes: 2be22f1941d5f ("Bluetooth: hci_event: Fix parsing of CIS Established Event") Signed-off-by: Pauli Virtanen Reviewed-by: Paul Menzel Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/hci_event.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 4f0a6116291e..fe7cdd67ad2a 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -6745,8 +6745,8 @@ static void hci_le_cis_established_evt(struct hci_dev *hdev, void *data, qos->ucast.out.latency = DIV_ROUND_CLOSEST(get_unaligned_le24(ev->p_latency), 1000); - qos->ucast.in.sdu = le16_to_cpu(ev->c_mtu); - qos->ucast.out.sdu = le16_to_cpu(ev->p_mtu); + qos->ucast.in.sdu = ev->c_bn ? le16_to_cpu(ev->c_mtu) : 0; + qos->ucast.out.sdu = ev->p_bn ? le16_to_cpu(ev->p_mtu) : 0; qos->ucast.in.phy = ev->c_phy; qos->ucast.out.phy = ev->p_phy; break; @@ -6760,8 +6760,8 @@ static void hci_le_cis_established_evt(struct hci_dev *hdev, void *data, qos->ucast.in.latency = DIV_ROUND_CLOSEST(get_unaligned_le24(ev->p_latency), 1000); - qos->ucast.out.sdu = le16_to_cpu(ev->c_mtu); - qos->ucast.in.sdu = le16_to_cpu(ev->p_mtu); + qos->ucast.out.sdu = ev->c_bn ? le16_to_cpu(ev->c_mtu) : 0; + qos->ucast.in.sdu = ev->p_bn ? le16_to_cpu(ev->p_mtu) : 0; qos->ucast.out.phy = ev->c_phy; qos->ucast.in.phy = ev->p_phy; break; -- 2.51.0