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authorRafael J. Wysocki <rjw@sisk.pl>2006-09-25 23:32:56 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-26 08:49:03 -0700
commitc8eb8b4025175f967af0ba8e933f23aa9954dc35 (patch)
tree1e7dcfe6472aa0cae05651e375bebb3e7b5b9eb8 /kernel
parent940864ddabdb180e02041c4dcd46ba6f9eee732f (diff)
downloadlinux-c8eb8b4025175f967af0ba8e933f23aa9954dc35.tar.gz
[PATCH] PM: make it possible to disable console suspending
Change suspend_console() so that it waits for all consoles to flush the
remaining messages and make it possible to switch the console suspending off
with the help of a Kconfig option.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Stefan Seyfried <seife@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/power/Kconfig11
-rw-r--r--kernel/printk.c3
2 files changed, 14 insertions, 0 deletions
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 619ecabf7c58..4b6e2f18e056 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -36,6 +36,17 @@ config PM_DEBUG
 	code. This is helpful when debugging and reporting various PM bugs, 
 	like suspend support.
 
+config DISABLE_CONSOLE_SUSPEND
+	bool "Keep console(s) enabled during suspend/resume (DANGEROUS)"
+	depends on PM && PM_DEBUG
+	default n
+	---help---
+	This option turns off the console suspend mechanism that prevents
+	debug messages from reaching the console during the suspend/resume
+	operations.  This may be helpful when debugging device drivers'
+	suspend/resume routines, but may itself lead to problems, for example
+	if netconsole is used.
+
 config PM_TRACE
 	bool "Suspend/resume event tracing"
 	depends on PM && PM_DEBUG && X86_32 && EXPERIMENTAL
diff --git a/kernel/printk.c b/kernel/printk.c
index 1149365e989e..771f5e861bcd 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -721,6 +721,7 @@ int __init add_preferred_console(char *name, int idx, char *options)
 	return 0;
 }
 
+#ifndef CONFIG_DISABLE_CONSOLE_SUSPEND
 /**
  * suspend_console - suspend the console subsystem
  *
@@ -728,6 +729,7 @@ int __init add_preferred_console(char *name, int idx, char *options)
  */
 void suspend_console(void)
 {
+	printk("Suspending console(s)\n");
 	acquire_console_sem();
 	console_suspended = 1;
 }
@@ -737,6 +739,7 @@ void resume_console(void)
 	console_suspended = 0;
 	release_console_sem();
 }
+#endif /* CONFIG_DISABLE_CONSOLE_SUSPEND */
 
 /**
  * acquire_console_sem - lock the console system for exclusive use.