serial: fix serial_txx9 console initialization

Since commit 97d97224ff361e08777fb33e0fd193ca877dac28 ("[SERIAL] Fix
console initialisation ordering"), serial_core calls ->pm() on
initialization even if the port was used for console.

This behaviour breaks serial_txx9 console since The serial_txx9 driver
initialize its port entirely on its ->pm() method if new state was 0.
This patch adds checking for oldstate value to fix this probelm.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/serial/serial_txx9.c b/drivers/serial/serial_txx9.c
index 6846a6c38b6..7ad21925869 100644
--- a/drivers/serial/serial_txx9.c
+++ b/drivers/serial/serial_txx9.c
@@ -657,7 +657,15 @@ static void
 serial_txx9_pm(struct uart_port *port, unsigned int state,
               unsigned int oldstate)
 {
-        if (state == 0)
+        /*
+         * If oldstate was -1 this is called from
+         * uart_configure_port().  In this case do not initialize the
+         * port now, because the port was already initialized (for
+         * non-console port) or should not be initialized here (for
+         * console port).  If we initialized the port here we lose
+         * serial console settings.
+         */
+        if (state == 0 && oldstate != -1)
                 serial_txx9_initialize(port);
 }