From: Hilda Wu hildawu@realtek.com
[ Upstream commit e848dbd364aca44c9d23c04bef964fab79e2b34f ]
Because mSBC frames do not need to be aligned to the SCO packet boundary. Using USB ALT 3 let HCI payload >= 60 bytes, let mSBC data satisfy 60 Bytes avoid payload unaligned situation and fixed some headset no voise issue.
USB Alt 3 supported also need HFP support transparent MTU in 72 Bytes.
Signed-off-by: Hilda Wu hildawu@realtek.com Signed-off-by: Marcel Holtmann marcel@holtmann.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/bluetooth/btusb.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c index 8f38a2a7da8c..b3c63e06838d 100644 --- a/drivers/bluetooth/btusb.c +++ b/drivers/bluetooth/btusb.c @@ -1721,6 +1721,13 @@ static void btusb_work(struct work_struct *work) * which work with WBS at all. */ 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)) + new_alts = 3; }
if (btusb_switch_alt_setting(hdev, new_alts) < 0)