MAINTAINERS | 2 ++ drivers/bluetooth/hci_bcm4377.c | 2 ++ include/net/bluetooth/bluetooth.h | 4 ++++ include/net/bluetooth/hci_core.h | 11 +++++++++++ net/bluetooth/Kconfig | 7 +++++++ net/bluetooth/Makefile | 1 + net/bluetooth/brcm.c | 29 +++++++++++++++++++++++++++++ net/bluetooth/brcm.h | 17 +++++++++++++++++ net/bluetooth/hci_conn.c | 28 ++++++++++++++++++++++++++++ net/bluetooth/l2cap_sock.c | 13 +++++++++++++ 10 files changed, 114 insertions(+)
From: Sasha Finkelstein <fnkl.kernel@gmail.com>
Certain Broadcom bluetooth chips (bcm4377/bcm4378/bcm438) need ACL
streams carrying audio to be set as "high priority" using a vendor
specific command to prevent 10-ish second-long dropouts whenever
something does a device scan. This patch sends the command when the
socket priority is set to TC_PRIO_INTERACTIVE, as BlueZ does for audio.
Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
---
Changes in v2:
- new ioctl got nack-ed, so let's use sk_priority as the trigger
- Link to v1: https://lore.kernel.org/r/20260407-brcm-prio-v1-1-f38b17376640@gmail.com
---
MAINTAINERS | 2 ++
drivers/bluetooth/hci_bcm4377.c | 2 ++
include/net/bluetooth/bluetooth.h | 4 ++++
include/net/bluetooth/hci_core.h | 11 +++++++++++
net/bluetooth/Kconfig | 7 +++++++
net/bluetooth/Makefile | 1 +
net/bluetooth/brcm.c | 29 +++++++++++++++++++++++++++++
net/bluetooth/brcm.h | 17 +++++++++++++++++
net/bluetooth/hci_conn.c | 28 ++++++++++++++++++++++++++++
net/bluetooth/l2cap_sock.c | 13 +++++++++++++
10 files changed, 114 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index c3fe46d7c4bc..81be021367ec 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2562,6 +2562,8 @@ F: include/dt-bindings/pinctrl/apple.h
F: include/linux/mfd/macsmc.h
F: include/linux/soc/apple/*
F: include/uapi/drm/asahi_drm.h
+F: net/bluetooth/brcm.c
+F: net/bluetooth/brcm.h
ARM/ARTPEC MACHINE SUPPORT
M: Jesper Nilsson <jesper.nilsson@axis.com>
diff --git a/drivers/bluetooth/hci_bcm4377.c b/drivers/bluetooth/hci_bcm4377.c
index 925d0a635945..5f79920c0306 100644
--- a/drivers/bluetooth/hci_bcm4377.c
+++ b/drivers/bluetooth/hci_bcm4377.c
@@ -2397,6 +2397,8 @@ static int bcm4377_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if (bcm4377->hw->broken_le_ext_adv_report_phy)
hci_set_quirk(hdev, HCI_QUIRK_FIXUP_LE_EXT_ADV_REPORT_PHY);
+ hci_set_brcm_capable(hdev);
+
pci_set_drvdata(pdev, bcm4377);
hci_set_drvdata(hdev, bcm4377);
SET_HCIDEV_DEV(hdev, &pdev->dev);
diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 69eed69f7f26..07a250673950 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -457,6 +457,7 @@ struct l2cap_ctrl {
};
struct hci_dev;
+struct hci_conn;
typedef void (*hci_req_complete_t)(struct hci_dev *hdev, u8 status, u16 opcode);
typedef void (*hci_req_complete_skb_t)(struct hci_dev *hdev, u8 status,
@@ -469,6 +470,9 @@ void hci_req_cmd_complete(struct hci_dev *hdev, u16 opcode, u8 status,
int hci_ethtool_ts_info(unsigned int index, int sk_proto,
struct kernel_ethtool_ts_info *ts_info);
+int hci_conn_setsockopt(struct hci_conn *conn, struct sock *sk, int level,
+ int optname, sockptr_t optval, unsigned int optlen);
+
#define HCI_REQ_START BIT(0)
#define HCI_REQ_SKB BIT(1)
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index a7bffb908c1e..947e7c2b08dd 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -642,6 +642,10 @@ struct hci_dev {
bool aosp_quality_report;
#endif
+#if IS_ENABLED(CONFIG_BT_BRCMEXT)
+ bool brcm_capable;
+#endif
+
int (*open)(struct hci_dev *hdev);
int (*close)(struct hci_dev *hdev);
int (*flush)(struct hci_dev *hdev);
@@ -1791,6 +1795,13 @@ static inline void hci_set_aosp_capable(struct hci_dev *hdev)
#endif
}
+static inline void hci_set_brcm_capable(struct hci_dev *hdev)
+{
+#if IS_ENABLED(CONFIG_BT_BRCMEXT)
+ hdev->brcm_capable = true;
+#endif
+}
+
static inline void hci_devcd_setup(struct hci_dev *hdev)
{
#ifdef CONFIG_DEV_COREDUMP
diff --git a/net/bluetooth/Kconfig b/net/bluetooth/Kconfig
index 6b2b65a66700..0f2a5fbcafc5 100644
--- a/net/bluetooth/Kconfig
+++ b/net/bluetooth/Kconfig
@@ -110,6 +110,13 @@ config BT_AOSPEXT
This options enables support for the Android Open Source
Project defined HCI vendor extensions.
+config BT_BRCMEXT
+ bool "Enable Broadcom extensions"
+ depends on BT
+ help
+ This option enables support for the Broadcom defined HCI
+ vendor extensions.
+
config BT_DEBUGFS
bool "Export Bluetooth internals in debugfs"
depends on BT && DEBUG_FS
diff --git a/net/bluetooth/Makefile b/net/bluetooth/Makefile
index a7eede7616d8..b4c9013a46ce 100644
--- a/net/bluetooth/Makefile
+++ b/net/bluetooth/Makefile
@@ -24,5 +24,6 @@ bluetooth-$(CONFIG_BT_LE) += iso.o
bluetooth-$(CONFIG_BT_LEDS) += leds.o
bluetooth-$(CONFIG_BT_MSFTEXT) += msft.o
bluetooth-$(CONFIG_BT_AOSPEXT) += aosp.o
+bluetooth-$(CONFIG_BT_BRCMEXT) += brcm.o
bluetooth-$(CONFIG_BT_DEBUGFS) += hci_debugfs.o
bluetooth-$(CONFIG_BT_SELFTEST) += selftest.o
diff --git a/net/bluetooth/brcm.c b/net/bluetooth/brcm.c
new file mode 100644
index 000000000000..9aa0a265ab3d
--- /dev/null
+++ b/net/bluetooth/brcm.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2026 The Asahi Linux Contributors
+ */
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include "brcm.h"
+
+int brcm_set_high_priority(struct hci_dev *hdev, u16 handle, bool enable)
+{
+ struct sk_buff *skb;
+ u8 cmd[3];
+
+ if (!hdev->brcm_capable)
+ return 0;
+
+ cmd[0] = handle;
+ cmd[1] = handle >> 8;
+ cmd[2] = !!enable;
+
+ skb = hci_cmd_sync(hdev, 0xfc57, sizeof(cmd), cmd, HCI_CMD_TIMEOUT);
+ if (IS_ERR(skb))
+ return PTR_ERR(skb);
+
+ kfree_skb(skb);
+ return 0;
+}
diff --git a/net/bluetooth/brcm.h b/net/bluetooth/brcm.h
new file mode 100644
index 000000000000..fdaee63bd1d2
--- /dev/null
+++ b/net/bluetooth/brcm.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2026 The Asahi Linux Contributors
+ */
+
+#if IS_ENABLED(CONFIG_BT_BRCMEXT)
+
+int brcm_set_high_priority(struct hci_dev *hdev, u16 handle, bool enable);
+
+#else
+
+static inline int brcm_set_high_priority(struct hci_dev *hdev, u16 handle, bool enable)
+{
+ return 0;
+}
+
+#endif
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 11d3ad8d2551..096163840f62 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -35,6 +35,7 @@
#include <net/bluetooth/iso.h>
#include <net/bluetooth/mgmt.h>
+#include "brcm.h"
#include "smp.h"
#include "eir.h"
@@ -3070,6 +3071,33 @@ int hci_conn_set_phy(struct hci_conn *conn, u32 phys)
}
}
+int hci_conn_setsockopt(struct hci_conn *conn, struct sock *sk, int level,
+ int optname, sockptr_t optval, unsigned int optlen)
+{
+ int val;
+ bool old_high, new_high, changed;
+
+ if (level != SOL_SOCKET)
+ return 0;
+
+ if (optname != SO_PRIORITY)
+ return 0;
+
+ if (optlen < sizeof(int))
+ return -EINVAL;
+
+ if (copy_from_sockptr(&val, optval, sizeof(val)))
+ return -EFAULT;
+
+ old_high = sk->sk_priority >= TC_PRIO_INTERACTIVE;
+ new_high = val >= TC_PRIO_INTERACTIVE;
+ changed = old_high != new_high;
+ if (!changed)
+ return 0;
+
+ return brcm_set_high_priority(conn->hdev, conn->handle, new_high);
+}
+
static int abort_conn_sync(struct hci_dev *hdev, void *data)
{
struct hci_conn *conn = data;
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 71e8c1b45bce..d5eef87accc4 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -891,6 +891,16 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
BT_DBG("sk %p", sk);
+ if (level == SOL_SOCKET) {
+ conn = chan->conn;
+ if (conn)
+ err = hci_conn_setsockopt(conn->hcon, sock->sk, level,
+ optname, optval, optlen);
+ if (err)
+ return err;
+ return sock_setsockopt(sock, level, optname, optval, optlen);
+ }
+
if (level == SOL_L2CAP)
return l2cap_sock_setsockopt_old(sock, optname, optval, optlen);
@@ -1931,6 +1941,9 @@ static struct sock *l2cap_sock_alloc(struct net *net, struct socket *sock,
INIT_LIST_HEAD(&l2cap_pi(sk)->rx_busy);
+ if (sock)
+ set_bit(SOCK_CUSTOM_SOCKOPT, &sock->flags);
+
chan = l2cap_chan_create();
if (!chan) {
sk_free(sk);
---
base-commit: bfe62a454542cfad3379f6ef5680b125f41e20f4
change-id: 20260407-brcm-prio-b630e6cc3834
Best regards,
--
Sasha Finkelstein <fnkl.kernel@gmail.com>Hi Sasha,
On Tue, Apr 7, 2026 at 1:46 PM Sasha Finkelstein via B4 Relay
<devnull+fnkl.kernel.gmail.com@kernel.org> wrote:
>
> From: Sasha Finkelstein <fnkl.kernel@gmail.com>
>
> Certain Broadcom bluetooth chips (bcm4377/bcm4378/bcm438) need ACL
> streams carrying audio to be set as "high priority" using a vendor
> specific command to prevent 10-ish second-long dropouts whenever
> something does a device scan. This patch sends the command when the
> socket priority is set to TC_PRIO_INTERACTIVE, as BlueZ does for audio.
>
> Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
> ---
> Changes in v2:
> - new ioctl got nack-ed, so let's use sk_priority as the trigger
> - Link to v1: https://lore.kernel.org/r/20260407-brcm-prio-v1-1-f38b17376640@gmail.com
> ---
> MAINTAINERS | 2 ++
> drivers/bluetooth/hci_bcm4377.c | 2 ++
> include/net/bluetooth/bluetooth.h | 4 ++++
> include/net/bluetooth/hci_core.h | 11 +++++++++++
> net/bluetooth/Kconfig | 7 +++++++
> net/bluetooth/Makefile | 1 +
> net/bluetooth/brcm.c | 29 +++++++++++++++++++++++++++++
> net/bluetooth/brcm.h | 17 +++++++++++++++++
> net/bluetooth/hci_conn.c | 28 ++++++++++++++++++++++++++++
> net/bluetooth/l2cap_sock.c | 13 +++++++++++++
> 10 files changed, 114 insertions(+)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c3fe46d7c4bc..81be021367ec 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2562,6 +2562,8 @@ F: include/dt-bindings/pinctrl/apple.h
> F: include/linux/mfd/macsmc.h
> F: include/linux/soc/apple/*
> F: include/uapi/drm/asahi_drm.h
> +F: net/bluetooth/brcm.c
> +F: net/bluetooth/brcm.h
>
> ARM/ARTPEC MACHINE SUPPORT
> M: Jesper Nilsson <jesper.nilsson@axis.com>
> diff --git a/drivers/bluetooth/hci_bcm4377.c b/drivers/bluetooth/hci_bcm4377.c
> index 925d0a635945..5f79920c0306 100644
> --- a/drivers/bluetooth/hci_bcm4377.c
> +++ b/drivers/bluetooth/hci_bcm4377.c
> @@ -2397,6 +2397,8 @@ static int bcm4377_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> if (bcm4377->hw->broken_le_ext_adv_report_phy)
> hci_set_quirk(hdev, HCI_QUIRK_FIXUP_LE_EXT_ADV_REPORT_PHY);
>
> + hci_set_brcm_capable(hdev);
> +
> pci_set_drvdata(pdev, bcm4377);
> hci_set_drvdata(hdev, bcm4377);
> SET_HCIDEV_DEV(hdev, &pdev->dev);
> diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
> index 69eed69f7f26..07a250673950 100644
> --- a/include/net/bluetooth/bluetooth.h
> +++ b/include/net/bluetooth/bluetooth.h
> @@ -457,6 +457,7 @@ struct l2cap_ctrl {
> };
>
> struct hci_dev;
> +struct hci_conn;
>
> typedef void (*hci_req_complete_t)(struct hci_dev *hdev, u8 status, u16 opcode);
> typedef void (*hci_req_complete_skb_t)(struct hci_dev *hdev, u8 status,
> @@ -469,6 +470,9 @@ void hci_req_cmd_complete(struct hci_dev *hdev, u16 opcode, u8 status,
> int hci_ethtool_ts_info(unsigned int index, int sk_proto,
> struct kernel_ethtool_ts_info *ts_info);
>
> +int hci_conn_setsockopt(struct hci_conn *conn, struct sock *sk, int level,
> + int optname, sockptr_t optval, unsigned int optlen);
> +
> #define HCI_REQ_START BIT(0)
> #define HCI_REQ_SKB BIT(1)
>
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index a7bffb908c1e..947e7c2b08dd 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -642,6 +642,10 @@ struct hci_dev {
> bool aosp_quality_report;
> #endif
>
> +#if IS_ENABLED(CONFIG_BT_BRCMEXT)
> + bool brcm_capable;
> +#endif
> +
> int (*open)(struct hci_dev *hdev);
> int (*close)(struct hci_dev *hdev);
> int (*flush)(struct hci_dev *hdev);
> @@ -1791,6 +1795,13 @@ static inline void hci_set_aosp_capable(struct hci_dev *hdev)
> #endif
> }
>
> +static inline void hci_set_brcm_capable(struct hci_dev *hdev)
> +{
> +#if IS_ENABLED(CONFIG_BT_BRCMEXT)
> + hdev->brcm_capable = true;
> +#endif
> +}
> +
> static inline void hci_devcd_setup(struct hci_dev *hdev)
> {
> #ifdef CONFIG_DEV_COREDUMP
> diff --git a/net/bluetooth/Kconfig b/net/bluetooth/Kconfig
> index 6b2b65a66700..0f2a5fbcafc5 100644
> --- a/net/bluetooth/Kconfig
> +++ b/net/bluetooth/Kconfig
> @@ -110,6 +110,13 @@ config BT_AOSPEXT
> This options enables support for the Android Open Source
> Project defined HCI vendor extensions.
>
> +config BT_BRCMEXT
> + bool "Enable Broadcom extensions"
> + depends on BT
> + help
> + This option enables support for the Broadcom defined HCI
> + vendor extensions.
> +
> config BT_DEBUGFS
> bool "Export Bluetooth internals in debugfs"
> depends on BT && DEBUG_FS
> diff --git a/net/bluetooth/Makefile b/net/bluetooth/Makefile
> index a7eede7616d8..b4c9013a46ce 100644
> --- a/net/bluetooth/Makefile
> +++ b/net/bluetooth/Makefile
> @@ -24,5 +24,6 @@ bluetooth-$(CONFIG_BT_LE) += iso.o
> bluetooth-$(CONFIG_BT_LEDS) += leds.o
> bluetooth-$(CONFIG_BT_MSFTEXT) += msft.o
> bluetooth-$(CONFIG_BT_AOSPEXT) += aosp.o
> +bluetooth-$(CONFIG_BT_BRCMEXT) += brcm.o
> bluetooth-$(CONFIG_BT_DEBUGFS) += hci_debugfs.o
> bluetooth-$(CONFIG_BT_SELFTEST) += selftest.o
> diff --git a/net/bluetooth/brcm.c b/net/bluetooth/brcm.c
> new file mode 100644
> index 000000000000..9aa0a265ab3d
> --- /dev/null
> +++ b/net/bluetooth/brcm.c
> @@ -0,0 +1,29 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2026 The Asahi Linux Contributors
> + */
> +
> +#include <net/bluetooth/bluetooth.h>
> +#include <net/bluetooth/hci_core.h>
> +
> +#include "brcm.h"
> +
> +int brcm_set_high_priority(struct hci_dev *hdev, u16 handle, bool enable)
> +{
> + struct sk_buff *skb;
> + u8 cmd[3];
> +
> + if (!hdev->brcm_capable)
> + return 0;
> +
> + cmd[0] = handle;
> + cmd[1] = handle >> 8;
Adding a packed struct and then using something like cpu_to_le16 is
probably preferable over above.
> + cmd[2] = !!enable;
> +
> + skb = hci_cmd_sync(hdev, 0xfc57, sizeof(cmd), cmd, HCI_CMD_TIMEOUT);
> + if (IS_ERR(skb))
> + return PTR_ERR(skb);
> +
> + kfree_skb(skb);
> + return 0;
> +}
> diff --git a/net/bluetooth/brcm.h b/net/bluetooth/brcm.h
> new file mode 100644
> index 000000000000..fdaee63bd1d2
> --- /dev/null
> +++ b/net/bluetooth/brcm.h
> @@ -0,0 +1,17 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2026 The Asahi Linux Contributors
> + */
> +
> +#if IS_ENABLED(CONFIG_BT_BRCMEXT)
> +
> +int brcm_set_high_priority(struct hci_dev *hdev, u16 handle, bool enable);
> +
> +#else
> +
> +static inline int brcm_set_high_priority(struct hci_dev *hdev, u16 handle, bool enable)
> +{
> + return 0;
> +}
> +
> +#endif
> diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
> index 11d3ad8d2551..096163840f62 100644
> --- a/net/bluetooth/hci_conn.c
> +++ b/net/bluetooth/hci_conn.c
> @@ -35,6 +35,7 @@
> #include <net/bluetooth/iso.h>
> #include <net/bluetooth/mgmt.h>
>
> +#include "brcm.h"
> #include "smp.h"
> #include "eir.h"
>
> @@ -3070,6 +3071,33 @@ int hci_conn_set_phy(struct hci_conn *conn, u32 phys)
> }
> }
>
> +int hci_conn_setsockopt(struct hci_conn *conn, struct sock *sk, int level,
> + int optname, sockptr_t optval, unsigned int optlen)
> +{
> + int val;
> + bool old_high, new_high, changed;
> +
> + if (level != SOL_SOCKET)
> + return 0;
> +
> + if (optname != SO_PRIORITY)
> + return 0;
> +
> + if (optlen < sizeof(int))
> + return -EINVAL;
> +
> + if (copy_from_sockptr(&val, optval, sizeof(val)))
> + return -EFAULT;
> +
> + old_high = sk->sk_priority >= TC_PRIO_INTERACTIVE;
> + new_high = val >= TC_PRIO_INTERACTIVE;
> + changed = old_high != new_high;
> + if (!changed)
> + return 0;
> +
> + return brcm_set_high_priority(conn->hdev, conn->handle, new_high);
The skb carries the priority (skb->priority), not sure why you need to
capture the sk_priority instead, doing so ignores the load balance
that hci_core performs to avoid starving connections.
> +}
> +
> static int abort_conn_sync(struct hci_dev *hdev, void *data)
> {
> struct hci_conn *conn = data;
> diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
> index 71e8c1b45bce..d5eef87accc4 100644
> --- a/net/bluetooth/l2cap_sock.c
> +++ b/net/bluetooth/l2cap_sock.c
> @@ -891,6 +891,16 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
>
> BT_DBG("sk %p", sk);
>
> + if (level == SOL_SOCKET) {
> + conn = chan->conn;
> + if (conn)
> + err = hci_conn_setsockopt(conn->hcon, sock->sk, level,
> + optname, optval, optlen);
> + if (err)
> + return err;
> + return sock_setsockopt(sock, level, optname, optval, optlen);
> + }
> +
> if (level == SOL_L2CAP)
> return l2cap_sock_setsockopt_old(sock, optname, optval, optlen);
>
> @@ -1931,6 +1941,9 @@ static struct sock *l2cap_sock_alloc(struct net *net, struct socket *sock,
>
> INIT_LIST_HEAD(&l2cap_pi(sk)->rx_busy);
>
> + if (sock)
> + set_bit(SOCK_CUSTOM_SOCKOPT, &sock->flags);
This is more complicated than it needs to be. I'd just add a new
callback, `hdev->set_priority(handle, skb->priority)`, so the driver
is called whenever it needs to elevate a connection's priority, that
said there could be cases where a connection needs its priority set
momentarily to transmit A2DP, followed by OBEX packets that are best
effort. Therefore, `hci_conn` will probably need to track the priority
so it can detect when it needs changing on a per skb basis.
> chan = l2cap_chan_create();
> if (!chan) {
> sk_free(sk);
>
> ---
> base-commit: bfe62a454542cfad3379f6ef5680b125f41e20f4
> change-id: 20260407-brcm-prio-b630e6cc3834
>
> Best regards,
> --
> Sasha Finkelstein <fnkl.kernel@gmail.com>
>
>
--
Luiz Augusto von Dentz
On Tue, 14 Apr 2026 at 16:00, Luiz Augusto von Dentz <luiz.dentz@gmail.com> wrote: > > + if (sock) > > + set_bit(SOCK_CUSTOM_SOCKOPT, &sock->flags); > > This is more complicated than it needs to be. I'd just add a new > callback, `hdev->set_priority(handle, skb->priority)`, so the driver > is called whenever it needs to elevate a connection's priority, that > said there could be cases where a connection needs its priority set > momentarily to transmit A2DP, followed by OBEX packets that are best > effort. Therefore, `hci_conn` will probably need to track the priority > so it can detect when it needs changing on a per skb basis. I have tested per-skb priorities, and unfortunately, this does not work. If something tries to send a low-priority packet (for example - a volume adjustment), a priority drop causes the same kind of dropout that is caused by scans. It appears that the only way to make this hardware work is to set the entire hci connection as high priority for as long as it is being used to transmit audio.
Hi Sasha, On Wed, Apr 15, 2026 at 8:34 AM Sasha Finkelstein <fnkl.kernel@gmail.com> wrote: > > On Tue, 14 Apr 2026 at 16:00, Luiz Augusto von Dentz > <luiz.dentz@gmail.com> wrote: > > > + if (sock) > > > + set_bit(SOCK_CUSTOM_SOCKOPT, &sock->flags); > > > > This is more complicated than it needs to be. I'd just add a new > > callback, `hdev->set_priority(handle, skb->priority)`, so the driver > > is called whenever it needs to elevate a connection's priority, that > > said there could be cases where a connection needs its priority set > > momentarily to transmit A2DP, followed by OBEX packets that are best > > effort. Therefore, `hci_conn` will probably need to track the priority > > so it can detect when it needs changing on a per skb basis. > > I have tested per-skb priorities, and unfortunately, this does not work. > If something tries to send a low-priority packet (for example - a volume > adjustment), a priority drop causes the same kind of dropout that is > caused by scans. It appears that the only way to make this hardware work > is to set the entire hci connection as high priority for as long as it > is being used to transmit audio. Ok, then maybe we should decrease the priority, so it can only go up. That said, in a multiple connection scenario, we cannot really tell what should be prioritized if we cannot momentarily decrease the priority. -- Luiz Augusto von Dentz
On Wed, 15 Apr 2026 at 17:19, Luiz Augusto von Dentz <luiz.dentz@gmail.com> wrote: > Ok, then maybe we should decrease the priority, so it can only go up. > That said, in a multiple connection scenario, we cannot really tell > what should be prioritized if we cannot momentarily decrease the > priority. I believe that the priority is only per-connection and is not designed to be used per-packet. On Android they change priority when an A2DP stream starts or stops, by sending the commands from userspace and are accepting that other things using the same hci connection will also have high priority.
On Tue, Apr 7, 2026 at 1:46 PM Sasha Finkelstein via B4 Relay <devnull+fnkl.kernel.gmail.com@kernel.org> wrote: > > From: Sasha Finkelstein <fnkl.kernel@gmail.com> > > Certain Broadcom bluetooth chips (bcm4377/bcm4378/bcm438) need ACL > streams carrying audio to be set as "high priority" using a vendor > specific command to prevent 10-ish second-long dropouts whenever > something does a device scan. This patch sends the command when the > socket priority is set to TC_PRIO_INTERACTIVE, as BlueZ does for audio. > > Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com> > --- > Changes in v2: > - new ioctl got nack-ed, so let's use sk_priority as the trigger > - Link to v1: https://lore.kernel.org/r/20260407-brcm-prio-v1-1-f38b17376640@gmail.com > --- Thank you so much for this! Reviewed-by: Neal Gompa <neal@gompa.dev> -- 真実はいつも一つ！/ Always, there's only one truth!
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