The patch titled
serial: set DTR in uart for kernel serial console
has been added to the -mm tree. Its filename is
serial-set-dtr-in-uart-for-kernel-serial-console.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: serial: set DTR in uart for kernel serial console
From: Yinghai Lu <Yinghai.Lu@xxxxxxx>
Some UARTs on other side need host uart DTR is set, otherwise will not
receive char from the host that kernel is runing during kernel boot stage.
BTW:
earlyprintk and early_uart are hard coded to set DTR/RTS.
Signed-off-by: Yinghai Lu <yinghai.lu@xxxxxxx>
Cc: Russell King <rmk@xxxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Cc: Bjorn Helgaas <bjorn.helgaas@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/serial/serial_core.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletion(-)
diff -puN drivers/serial/serial_core.c~serial-set-dtr-in-uart-for-kernel-serial-console drivers/serial/serial_core.c
--- a/drivers/serial/serial_core.c~serial-set-dtr-in-uart-for-kernel-serial-console
+++ a/drivers/serial/serial_core.c
@@ -2304,8 +2304,13 @@ int uart_add_one_port(struct uart_driver
* It may be that the port was not available.
*/
if (port->type != PORT_UNKNOWN &&
- port->cons && !(port->cons->flags & CON_ENABLED))
+ port->cons && !(port->cons->flags & CON_ENABLED)) {
+ /* some uarts on other side don't support no flow control. So we set
+ * DTR in host uart to make them happy --- YHLU
+ */
+ port->mctrl |= TIOCM_DTR;
register_console(port->cons);
+ }
/*
* Ensure UPF_DEAD is not set.
_
Patches currently in -mm which might be from Yinghai.Lu@xxxxxxx are
serial-set-dtr-in-uart-for-kernel-serial-console.patch
-
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