From 4464d05a258b6c76ed019479cf606e1f4495da78 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 3 Jul 2009 08:30:32 -0500
Subject: [PATCH] serial/console: rt support fixup

commit d4ea9d10593e414eba0d5ddc26370801b1a7fdbb in tip.

The serial console printk path grew a new spinlock - which is rather
heavy - so instead of converting it to raw, use the sysrq/oops path
of only taking the lock if we can, on PREEMPT_RT.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 708b6d9..ea995f4 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2740,7 +2740,7 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count)
 
 	touch_nmi_watchdog();
 
-	if (up->port.sysrq || oops_in_progress)
+	if (up->port.sysrq || oops_in_progress || preempt_rt())
 		locked = spin_trylock_irqsave(&up->port.lock, flags);
 	else
 		spin_lock_irqsave(&up->port.lock, flags);
-- 
1.7.1.1