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[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>
hifive-unleashed-5.1
Rafael J. Wysocki 2006-09-25 23:32:56 -07:00 committed by Linus Torvalds
parent 940864ddab
commit c8eb8b4025
3 changed files with 19 additions and 0 deletions
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5
include/linux/console.h
View File

@ -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

11
kernel/power/Kconfig
View File

@ -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

3
kernel/printk.c
View File

@ -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.