From 2eda5345e4ef61b35101b4fef58417a41d8d53fd Mon Sep 17 00:00:00 2001 From: Sergey Organov Date: Wed, 28 Aug 2019 21:37:51 +0300 Subject: [PATCH] serial: imx: get rid of unbounded busy-waiting loop imx_set_termios(): remove busy-waiting "drain Tx FIFO" loop. Worse yet, it was potentially unbounded wait due to RTS/CTS (hardware) handshake. Let user space ensure draining is done before termios change, if draining is needed in the first place. Signed-off-by: Sergey Organov Link: https://lore.kernel.org/r/1567017475-11919-2-git-send-email-sorganov@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index d9a73c7683ea..47b6156f5b2c 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1644,7 +1644,7 @@ imx_uart_set_termios(struct uart_port *port, struct ktermios *termios, uart_update_timeout(port, termios->c_cflag, baud); /* - * disable interrupts and drain transmitter + * disable interrupts */ old_ucr1 = imx_uart_readl(sport, UCR1); imx_uart_writel(sport, @@ -1652,9 +1652,6 @@ imx_uart_set_termios(struct uart_port *port, struct ktermios *termios, UCR1); imx_uart_writel(sport, old_ucr2 & ~UCR2_ATEN, UCR2); - while (!(imx_uart_readl(sport, USR2) & USR2_TXDC)) - barrier(); - /* then, disable everything */ imx_uart_writel(sport, old_ucr2 & ~(UCR2_TXEN | UCR2_RXEN | UCR2_ATEN), UCR2);