Re: [Linux-kernel] [PATCH] tty: serial: 8250: add CON_CONSDEV to flags

From: Ben Dooks
Date: Tue Oct 18 2016 - 12:24:48 EST


On 18/10/16 17:15, Jiri Slaby wrote:
On 06/21/2016, 05:19 PM, Matthew Leach wrote:
When using the 8250 as a boot console and the main console results in
messages being printed twice. The console framework will only
unregister boot consoles if a new console is registered with the
CON_CONSDEV flag set.

Set this flag for the univ8250 console to prevent double-registration.

Signed-off-by: Matthew Leach <matthew.leach@xxxxxxxxxxxxxxx>
---
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 2f4f5ee..7a7453d 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -675,7 +675,7 @@ static struct console univ8250_console = {
.device = uart_console_device,
.setup = univ8250_console_setup,
.match = univ8250_console_match,
- .flags = CON_PRINTBUFFER | CON_ANYTIME,
+ .flags = CON_PRINTBUFFER | CON_ANYTIME | CON_CONSDEV,

This patch breaks console= parameter handling. Passing:
console=ttyS0 console=tty0
no longer means /dev/console is tty0 and it should be as is documented.

I have not investigated further yet.

Ok, thanks.
I'll need to find Matthew Leach's new address as he's moved jobs.

--
Ben Dooks http://www.codethink.co.uk/
Senior Engineer Codethink - Providing Genius