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Commit c8eb8b40 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Linus Torvalds
Browse files

[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: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Cc: Stefan Seyfried <seife@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 940864dd

include/linux/console.h

+5 −0
Original line number Diff line number Diff line
@@ -120,9 +120,14 @@ extern void console_stop(struct console *); 
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

kernel/power/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -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

kernel/printk.c

+3 −0
Original line number Diff line number Diff line
@@ -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.