This is a note to let you know that I've just added the patch titled Bluetooth: btusb: fix bt fiwmare downloading failure issue for qca btsoc. to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bluetooth-btusb-fix-bt-fiwmare-downloading-failure-i.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 50537e96da2221d085d3df434530046c42391710 Author: Tim Jiang <tjiang@xxxxxxxxxxxxxx> Date: Tue Jun 1 17:57:10 2021 +0800 Bluetooth: btusb: fix bt fiwmare downloading failure issue for qca btsoc. [ Upstream commit 4f00bfb372674d586c4a261bfc595cbce101fbb6 ] This is btsoc timing issue, after host start to downloading bt firmware, ep2 need time to switch from function acl to function dfu, so host add 20ms delay as workaround. Signed-off-by: Tim Jiang <tjiang@xxxxxxxxxxxxxx> Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c index 7039a58a6a4e..3d62f17111cb 100644 --- a/drivers/bluetooth/btusb.c +++ b/drivers/bluetooth/btusb.c @@ -2555,6 +2555,11 @@ static int btusb_setup_qca_download_fw(struct hci_dev *hdev, sent += size; count -= size; + /* ep2 need time to switch from function acl to function dfu, + * so we add 20ms delay here. + */ + msleep(20); + while (count) { size = min_t(size_t, count, QCA_DFU_PACKET_LEN);