From f2bfdb0628d50339a70de475eb2be1c4c1eb9014 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 30 Oct 2015 11:39:04 +0900 Subject: [PATCH] serial: 8250_early: confirm empty transmitter after sending characters The current code waits until the transmitter becomes empty, before sending each character, and after finishing the whole string. This seems a bit redundant. It can be more efficient by checking the transmitter only after sending each character. This should be safe because the transmitter is already empty at the first entry of serial_putc(). Signed-off-by: Masahiro Yamada Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_early.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c index 5afc4d4..20ec27b 100644 --- a/drivers/tty/serial/8250/8250_early.c +++ b/drivers/tty/serial/8250/8250_early.c @@ -87,8 +87,8 @@ static void __init wait_for_xmitr(struct uart_port *port) static void __init serial_putc(struct uart_port *port, int c) { - wait_for_xmitr(port); serial8250_early_out(port, UART_TX, c); + wait_for_xmitr(port); } static void __init early_serial8250_write(struct console *console, @@ -98,9 +98,6 @@ static void __init early_serial8250_write(struct console *console, struct uart_port *port = &device->port; uart_console_write(port, s, count, serial_putc); - - /* Wait for transmitter to become empty */ - wait_for_xmitr(port); } static void __init init_port(struct earlycon_device *device) -- 2.7.4