Hi Greg,
On Mon, Feb 24, 2025 at 2:10 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Mon, Feb 24, 2025 at 12:52:32PM +0800, Hsin-chen Chuang wrote:
> > From: Hsin-chen Chuang <chharry@xxxxxxxxxxxx>
> >
> > Automatically configure the altsetting for USER_CHANNEL when a SCO is
> > connected. This adds support for the USER_CHANNEL to transfer SCO data
> > over USB transport.
> >
> > Fixes: b16b327edb4d ("Bluetooth: btusb: add sysfs attribute to control USB alt setting")
> > Signed-off-by: Hsin-chen Chuang <chharry@xxxxxxxxxxxx>
> > ---
> >
> > Changes in v2:
> > - Give up tracking the SCO handles. Only configure the altsetting when
> > SCO connected.
> > - Put the change behind Kconfig/module parameter
> >
> > drivers/bluetooth/Kconfig | 11 ++++++++++
> > drivers/bluetooth/btusb.c | 46 +++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 57 insertions(+)
> >
> > diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
> > index 4ab32abf0f48..7c497f878732 100644
> > --- a/drivers/bluetooth/Kconfig
> > +++ b/drivers/bluetooth/Kconfig
> > @@ -56,6 +56,17 @@ config BT_HCIBTUSB_POLL_SYNC
> > Say Y here to enable USB poll_sync for Bluetooth USB devices by
> > default.
> >
> > +config BT_HCIBTUSB_AUTO_SET_ISOC_ALT
> > + bool "Auto set isoc_altsetting for USER_CHANNEL when SCO connected"
> > + depends on BT_HCIBTUSB
> > + default n
> > + help
> > + Say Y here to enable auto set isoc_altsetting for USER_CHANNEL
> > + when SCO connected
> > +
> > + This can be overridden by passing btusb.auto_set_isoc_alt=[y|n]
> > + on the kernel commandline.
> > +
> > config BT_HCIBTUSB_BCM
> > bool "Broadcom protocol support"
> > depends on BT_HCIBTUSB
> > diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> > index de3fa725d210..af93d757911b 100644
> > --- a/drivers/bluetooth/btusb.c
> > +++ b/drivers/bluetooth/btusb.c
> > @@ -34,6 +34,8 @@ static bool force_scofix;
> > static bool enable_autosuspend = IS_ENABLED(CONFIG_BT_HCIBTUSB_AUTOSUSPEND);
> > static bool enable_poll_sync = IS_ENABLED(CONFIG_BT_HCIBTUSB_POLL_SYNC);
> > static bool reset = true;
> > +static bool auto_set_isoc_alt =
> > + IS_ENABLED(CONFIG_BT_HCIBTUSB_AUTO_SET_ISOC_ALT);
> >
> > static struct usb_driver btusb_driver;
> >
> > @@ -1113,6 +1115,42 @@ static inline void btusb_free_frags(struct btusb_data *data)
> > spin_unlock_irqrestore(&data->rxlock, flags);
> > }
> >
> > +static void btusb_sco_connected(struct btusb_data *data, struct sk_buff *skb)
> > +{
> > + struct hci_event_hdr *hdr = (void *) skb->data;
> > + struct hci_ev_sync_conn_complete *ev =
> > + (void *) skb->data + sizeof(*hdr);
> > + struct hci_dev *hdev = data->hdev;
> > + unsigned int notify_air_mode;
> > +
> > + if (hci_skb_pkt_type(skb) != HCI_EVENT_PKT)
> > + return;
> > +
> > + if (skb->len < sizeof(*hdr) || hdr->evt != HCI_EV_SYNC_CONN_COMPLETE)
> > + return;
> > +
> > + if (skb->len != sizeof(*hdr) + sizeof(*ev) || ev->status)
> > + return;
> > +
> > + switch (ev->air_mode) {
> > + case BT_CODEC_CVSD:
> > + notify_air_mode = HCI_NOTIFY_ENABLE_SCO_CVSD;
> > + break;
> > +
> > + case BT_CODEC_TRANSPARENT:
> > + notify_air_mode = HCI_NOTIFY_ENABLE_SCO_TRANSP;
> > + break;
> > +
> > + default:
> > + return;
> > + }
> > +
> > + bt_dev_info(hdev, "enabling SCO with air mode %u", ev->air_mode);
> > + data->sco_num = 1;
> > + data->air_mode = notify_air_mode;
> > + schedule_work(&data->work);
> > +}
> > +
> > static int btusb_recv_event(struct btusb_data *data, struct sk_buff *skb)
> > {
> > if (data->intr_interval) {
> > @@ -1120,6 +1158,11 @@ static int btusb_recv_event(struct btusb_data *data, struct sk_buff *skb)
> > schedule_delayed_work(&data->rx_work, 0);
> > }
> >
> > + /* Configure altsetting for HCI_USER_CHANNEL on SCO connected */
> > + if (auto_set_isoc_alt &&
> > + hci_dev_test_flag(data->hdev, HCI_USER_CHANNEL))
> > + btusb_sco_connected(data, skb);
> > +
> > return data->recv_event(data->hdev, skb);
> > }
> >
> > @@ -4354,6 +4397,9 @@ MODULE_PARM_DESC(enable_autosuspend, "Enable USB autosuspend by default");
> > module_param(reset, bool, 0644);
> > MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
> >
> > +module_param(auto_set_isoc_alt, bool, 0644);
> > +MODULE_PARM_DESC(auto_set_isoc_alt, "Auto set isoc_altsetting for USER_CHANNEL when SCO connected");
>
> This is not the 1990's, why are you adding new module parameters when we
> have so many other more proper ways to do this? And really, this would
Sorry but could you please provide an example to guard a feature like this.
> not work at all for multiple controllers in teh same system, right?
Do you mean we can't have separate parameters for different
controllers? Yes that's true, but why would a user want the different
behavior on the same machine?
> That should cause it to not even be considered at all as a viable
> solution.
>
> confused,
>
> greg k-h
--
Best Regards,
Hsin-chen
