[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>
diff --git a/include/linux/console.h b/include/linux/console.h
index 3bdf215..76a1807 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -120,9 +120,14 @@
extern void console_start(struct console *);
extern int is_console_locked(void);
+#ifndef CONFIG_DISABLE_CONSOLE_SUSPEND
/* Suspend and resume console messages over PM events */
extern void suspend_console(void);
extern void resume_console(void);
+#else
+static inline void suspend_console(void) {}
+static inline void resume_console(void) {}
+#endif /* CONFIG_DISABLE_CONSOLE_SUSPEND */
/* Some debug stub to catch some of the obvious races in the VT code */
#if 1
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 619ecab..4b6e2f1 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -36,6 +36,17 @@
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 1149365..771f5e8 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -721,6 +721,7 @@
return 0;
}
+#ifndef CONFIG_DISABLE_CONSOLE_SUSPEND
/**
* suspend_console - suspend the console subsystem
*
@@ -728,6 +729,7 @@
*/
void suspend_console(void)
{
+ printk("Suspending console(s)\n");
acquire_console_sem();
console_suspended = 1;
}
@@ -737,6 +739,7 @@
console_suspended = 0;
release_console_sem();
}
+#endif /* CONFIG_DISABLE_CONSOLE_SUSPEND */
/**
* acquire_console_sem - lock the console system for exclusive use.