Bluetooth: btnxpuart: Fix glitches seen in dual A2DP streaming

[ Upstream commit 7de119b ]

This fixes a regression caused by previous commit for fixing truncated
ACL data, which is causing some intermittent glitches when running two
A2DP streams.

serdev_device_write_buf() is the root cause of the glitch, which is
reverted, and the TX work will continue to write until the queue is empty.

This change fixes both issues. No A2DP streaming glitches or truncated
ACL data issue observed.

Fixes: 8023dd2 ("Bluetooth: btnxpuart: Fix driver sending truncated data")
Fixes: 689ca16 ("Bluetooth: NXP: Add protocol support for NXP Bluetooth chipsets")
Signed-off-by: Neeraj Sanjay Kale <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
(cherry picked from commit 377d47fda395961cb99d28907fcbaf5198325c0b)
Signed-off-by: Jack Vogel <[email protected]>

Author: NeerajSanjayKale

drivers/bluetooth/btnxpuart.c

@@ -1336,13 +1336,12 @@ static void btnxpuart_tx_work(struct work_struct *work)
 
 	while ((skb = nxp_dequeue(nxpdev))) {
 		len = serdev_device_write_buf(serdev, skb->data, skb->len);
-		serdev_device_wait_until_sent(serdev, 0);
 		hdev->stat.byte_tx += len;
 
 		skb_pull(skb, len);
 		if (skb->len > 0) {
 			skb_queue_head(&nxpdev->txq, skb);
-			break;
+			continue;
 		}
 
 		switch (hci_skb_pkt_type(skb)) {