From fa4587bf6a3490f446d9087a8c6f98aaa98ad33f Mon Sep 17 00:00:00 2001 From: Heikki Krogerus Date: Thu, 5 Sep 2013 17:34:52 +0300 Subject: [PATCH] serial: 8250: don't change the fifo trigger level when using dma DMA engines usually expect the fifo trigger level to be aligned with the burst size. It should not be changed even with small baud rates. This will fix an issue with Designware DMA engine where the data can not be transferred over UART with lower baud rates then 2400. Signed-off-by: Heikki Krogerus Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 570df9d2a5d2f..e33d38cb170f9 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -2322,7 +2322,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) { fcr = uart_config[port->type].fcr; - if (baud < 2400 || fifo_bug) { + if ((baud < 2400 && !up->dma) || fifo_bug) { fcr &= ~UART_FCR_TRIGGER_MASK; fcr |= UART_FCR_TRIGGER_1; } -- 2.39.5