From: Pali Rohár <pali@kernel.org> stable inclusion from linux-4.19.209 commit 4a319dd66f497bb5e8441950af48c845c0670849 -------------------------------- commit 74e1eb3b4a1ef2e564b4bdeb6e92afe844e900de upstream. Driver's tx_empty callback should signal when the transmit shift register is empty. So when the last character has been sent. STAT_TX_FIFO_EMP bit signals only that HW transmit FIFO is empty, which happens when the last byte is loaded into transmit shift register. STAT_TX_EMP bit signals when the both HW transmit FIFO and transmit shift register are empty. So replace STAT_TX_FIFO_EMP check by STAT_TX_EMP in mvebu_uart_tx_empty() callback function. Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port") Cc: stable <stable@vger.kernel.org> Signed-off-by: Pali Rohár <pali@kernel.org> Link: https://lore.kernel.org/r/20210911132017.25505-1-pali@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/tty/serial/mvebu-uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index 170e446a2f625..494e476ac8db9 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c @@ -162,7 +162,7 @@ static unsigned int mvebu_uart_tx_empty(struct uart_port *port) st = readl(port->membase + UART_STAT); spin_unlock_irqrestore(&port->lock, flags); - return (st & STAT_TX_FIFO_EMP) ? TIOCSER_TEMT : 0; + return (st & STAT_TX_EMP) ? TIOCSER_TEMT : 0; } static unsigned int mvebu_uart_get_mctrl(struct uart_port *port) -- 2.25.1