linux-kernel - [PATCH] PM / sleep: console flush during suspend if no_console

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Date:	Mon, 21 Dec 2015 12:01:40 +0530
From:	Bibek Basu <bbasu@...dia.com>
To:	rjw@...ysocki.net, len.brown@...el.com, pavel@....cz
CC:	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	bbasu@...dia.com
Subject: [PATCH] PM / sleep: console flush during suspend if no_console_suspend enabled

On multicore CPUs, sometimes debug console logs are not flushed
if you have VT consoles also enabled. Reason being console_lock
is taken by secondary/nonboot cpus which are  disabled as part
of suspend.This patch flushes the console before disabling
nonboot cpus

Signed-off-by: Bibek Basu <bbasu@...dia.com>
---
 kernel/power/suspend.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index f9fe133..42c5912 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -352,6 +352,16 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
 		goto Platform_wake;
 	}
 
+	/*
+	 * Flush console buffer if console_suspend_enabled cleared.
+	 * This will enable console flush if console_lock is taken
+	 * by nonboot cpus which will soon be disabled below.
+	 */
+	if (!console_suspend_enabled) {
+		console_lock();
+		console_unlock();
+	}
+
 	error = disable_nonboot_cpus();
 	if (error || suspend_test(TEST_CPUS))
 		goto Enable_cpus;
-- 
2.1.4

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