[lkml]   [2020]   [Dec]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH RESEND] tty/serial/imx: Enable TXEN bit in imx_poll_init().
From: Mingrui Ren <>

As described in Documentation, poll_init() is called by kgdb to initialize
hardware which supports both poll_put_char() and poll_get_char().

It's necessary to enable TXEN bit, otherwise, it will cause hardware fault
and kernel panic when calling imx_poll_put_char().

Generally, if use /dev/ttymxc0 as kgdb console as well as system
console, ttymxc0 is initialized early by system console which does enable
TXEN bit.But when use /dev/ttymxc1 as kgbd console, ttymxc1 is only
initialized by imx_poll_init() cannot enable the TXEN bit, which will
cause kernel panic.

Signed-off-by: Mingrui Ren <>
Hi, thanks for your reply, and sorry for sending two identical emails.
The email service I used before seems to have some problems,
so I switched to gmail.This is the "correct" version, please check.

drivers/tty/serial/imx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 43c6d7142fdd..7c665db3d897 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1829,7 +1829,7 @@ static int imx_uart_poll_init(struct uart_port *port)
ucr1 |= UCR1_UARTEN;

- ucr2 |= UCR2_RXEN;
+ ucr2 |= UCR2_RXEN|UCR2_TXEN;
ucr2 &= ~UCR2_ATEN;

imx_uart_writel(sport, ucr1, UCR1);
 \ /
  Last update: 2020-12-01 16:07    [W:0.072 / U:1.732 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site