[PATCH 5.13 165/266] Bluetooth: btusb: Add support USB ALT 3 for WBS

Greg Kroah-Hartman
2021-07-15T19:42:53Z

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 90872099d9c3..4c18a85a1070 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -1751,6 +1751,13 @@ 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)
--
2.30.2