Re: [PATCH v13 12/12] Bluetooth: Allow usb to auto-suspend when SCO use non-HCI transport

Hi Luiz,

quoted

Currently usb tranport is not allowed to suspend when SCO over
HCI tranport is active.

This patch shall enable the usb tranport to suspend when SCO
link use non-HCI transport

Signed-off-by: Chethan T N <redacted>
Signed-off-by: Kiran K <redacted>
---

Notes:
   changes in v13:
   - suspend usb in HFP offload use case

drivers/bluetooth/btintel.c       |  2 +-
include/net/bluetooth/bluetooth.h |  4 ++++
net/bluetooth/hci_event.c         | 20 +++++++++++---------
net/bluetooth/sco.c               |  2 +-
4 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c
index 6091b691ddc2..2d64e289cf6e 100644
--- a/drivers/bluetooth/btintel.c
+++ b/drivers/bluetooth/btintel.c

@@ -2215,7 +2215,7 @@ static int btintel_get_codec_config_data(struct hci_dev *hdev,

static int btintel_get_data_path_id(struct hci_dev *hdev, __u8 *data_path_id)
{
       /* Intel uses 1 as data path id for all the usecases */
-       *data_path_id = 1;
+       *data_path_id = BT_SCO_PCM_PATH;
       return 0;
}

diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index c1fa90fb7502..9e2745863b33 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h

@@ -177,6 +177,10 @@ struct bt_codecs {

#define CODING_FORMAT_TRANSPARENT      0x03
#define CODING_FORMAT_MSBC             0x05

+/* Audio data transport path used for SCO */
+#define BT_SCO_HCI_PATH 0x00
+#define BT_SCO_PCM_PATH 0x01

If this is in fact vendor specific perhaps you should be declared in
btintel.h not here.

quoted

+
__printf(1, 2)
void bt_info(const char *fmt, ...);
__printf(1, 2)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index b48e24629fa4..7ff11cba89cf 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c

@@ -4516,15 +4516,17 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,

       bt_dev_dbg(hdev, "SCO connected with air mode: %02x", ev->air_mode);

-       switch (ev->air_mode) {
-       case 0x02:
-               if (hdev->notify)
-                       hdev->notify(hdev, HCI_NOTIFY_ENABLE_SCO_CVSD);
-               break;
-       case 0x03:
-               if (hdev->notify)
-                       hdev->notify(hdev, HCI_NOTIFY_ENABLE_SCO_TRANSP);
-               break;
+       if (conn->codec.data_path == BT_SCO_HCI_PATH) {
+               switch (ev->air_mode) {
+               case 0x02:
+                       if (hdev->notify)
+                               hdev->notify(hdev, HCI_NOTIFY_ENABLE_SCO_CVSD);
+                       break;
+               case 0x03:
+                       if (hdev->notify)
+                               hdev->notify(hdev, HCI_NOTIFY_ENABLE_SCO_TRANSP);
+                       break;
+               }

Hmm I think we might need to notify the driver to enable PCM routing
so the likes of btusb can call
usb_disable_endpoint/usb_enable_endpoint for example since in theory
userspace may choose to switch from software to hardware offload and
vice-versa, note without calling usb_disable_endpoint there might not
be much power saving after all since the endpoint will remain active
or do we actually have a good explanation why it shall not be called
when using PCM routing? Note that usb_set_interface will call
usb_enable_interface that will then call usb_enable_endpoint so
perhaps we need to call usb_disable_interface, either way we can't
assume the platform will be restricted to only use one or the other.

actually for the Intel hardware we shouldn’t do this at all. We should switch to vendor specific SCO over bulk endpoints and not claim the ISOC endpoints at all.

Regards

Marcel