Re: [PATCH] tty: serial: men_z135_uart: Wakeup UART after transmitting

From: Johannes Thumshirn <redacted>

Call uart_write_wakeup() after writing the hardware FIFO and updateing the FIFO
pointers.

This fixes high latency and jitter on PPP over Serial links.

Reported-by: Jun Shih <redacted>
Tested-by: Jun Shih <redacted>
Signed-off-by: Johannes Thumshirn <redacted>
---
 drivers/tty/serial/men_z135_uart.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/men_z135_uart.c b/drivers/tty/serial/men_z135_uart.c
index c9d1854..30e9e60 100644
--- a/drivers/tty/serial/men_z135_uart.c
+++ b/drivers/tty/serial/men_z135_uart.c

@@ -308,9 +308,6 @@ static void men_z135_handle_tx(struct men_z135_port *uart)
 	if (port->x_char)
 		goto out;

-	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
-		uart_write_wakeup(port);
-
 	/* calculate bytes to copy */
 	qlen = uart_circ_chars_pending(xmit);
 	if (qlen <= 0)

@@ -357,6 +354,9 @@ static void men_z135_handle_tx(struct men_z135_port *uart)

 	port->icount.tx += n;

+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
 irq_en:
 	if (!uart_circ_empty(xmit))
 		men_z135_reg_set(uart, MEN_Z135_CONF_REG, MEN_Z135_IER_TXCIEN);
--

1.9.1