diff options
Diffstat (limited to 'drivers/bluetooth/btusb.c')
| -rw-r--r-- | drivers/bluetooth/btusb.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c index afd2b1f12d49..e0859f4e2807 100644 --- a/drivers/bluetooth/btusb.c +++ b/drivers/bluetooth/btusb.c @@ -486,6 +486,7 @@ static const struct dmi_system_id btusb_needs_reset_resume_table[] = { #define BTUSB_HW_RESET_ACTIVE 12 #define BTUSB_TX_WAIT_VND_EVT 13 #define BTUSB_WAKEUP_DISABLE 14 +#define BTUSB_USE_ALT3_FOR_WBS 15 struct btusb_data { struct hci_dev *hdev; @@ -1718,16 +1719,20 @@ static void btusb_work(struct work_struct *work) /* Bluetooth USB spec recommends alt 6 (63 bytes), but * many adapters do not support it. Alt 1 appears to * work for all adapters that do not have alt 6, and - * which work with WBS at all. + * which work with WBS at all. Some devices prefer + * alt 3 (HCI payload >= 60 Bytes let air packet + * data satisfy 60 bytes), requiring + * MTU >= 3 (packets) * 25 (size) - 3 (headers) = 72 + * see also Core spec 5, vol 4, B 2.1.1 & Table 2.1. */ - new_alts = btusb_find_altsetting(data, 6) ? 6 : 1; - /* Because mSBC frames do not need to be aligned to the - * SCO packet boundary. If support the Alt 3, use the - * Alt 3 for HCI payload >= 60 Bytes let air packet - * data satisfy 60 bytes. - */ - if (new_alts == 1 && btusb_find_altsetting(data, 3)) + if (btusb_find_altsetting(data, 6)) + new_alts = 6; + else if (btusb_find_altsetting(data, 3) && + hdev->sco_mtu >= 72 && + test_bit(BTUSB_USE_ALT3_FOR_WBS, &data->flags)) new_alts = 3; + else + new_alts = 1; } if (btusb_switch_alt_setting(hdev, new_alts) < 0) @@ -4170,6 +4175,7 @@ static int btusb_probe(struct usb_interface *intf, * (DEVICE_REMOTE_WAKEUP) */ set_bit(BTUSB_WAKEUP_DISABLE, &data->flags); + set_bit(BTUSB_USE_ALT3_FOR_WBS, &data->flags); } if (!reset) |