Bluetooth: btnxpuart: Fix glitches seen in dual A2DP streaming

JIRA: https://issues.redhat.com/browse/RHEL-74483

commit 7de119b
Author: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Date:   Mon Jan 20 19:49:46 2025 +0530

    Bluetooth: btnxpuart: Fix glitches seen in dual A2DP streaming

    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 <neeraj.sanjaykale@nxp.com>
    Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Signed-off-by: Bastien Nocera <bnocera@redhat.com>

Author: Bastien Nocera

drivers/bluetooth/btnxpuart.c

@@ -1381,13 +1381,12 @@ 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)) {