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 RS-232 devices require DTR to be asserted before they can be used. DTR
is normally asserted in uart_startup() when the port is opened. But we don't
actually open serial console ports, so assert DTR when the port is added.
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 | 8 +++++++-
1 files changed, 7 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
@@ -2303,8 +2303,14 @@ 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)) {
+ /*
+ * We normally assert DTR when a port is opened, but serial
+ * console devices aren't actually opened, so do it here.
+ */
+ uart_set_mctrl(port, TIOCM_DTR);
register_console(port->cons);
+ }
/*
* Ensure UPF_DEAD is not set.
_
Patches currently in -mm which might be from Yinghai.Lu@xxxxxxx are
console-more-buf-for-index-parsing.patch
console-console-handover-to-preferred-console.patch
serial-convert-early_uart-to-earlycon-for-8250.patch
serial-set-dtr-in-uart-for-kernel-serial-console.patch
-
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