Add support for suspending and resuming the whole console subsystem
Trying to suspend/resume with console messages flying all around is doomed to failure, when the devices that the messages are trying to go to are being shut down. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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5603509137
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@ -117,6 +117,10 @@ extern void console_stop(struct console *);
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extern void console_start(struct console *);
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extern void console_start(struct console *);
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extern int is_console_locked(void);
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extern int is_console_locked(void);
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/* Suspend and resume console messages over PM events */
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extern void suspend_console(void);
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extern void resume_console(void);
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/* Some debug stub to catch some of the obvious races in the VT code */
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/* Some debug stub to catch some of the obvious races in the VT code */
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#if 1
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#if 1
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#define WARN_CONSOLE_UNLOCKED() WARN_ON(!is_console_locked() && !oops_in_progress)
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#define WARN_CONSOLE_UNLOCKED() WARN_ON(!is_console_locked() && !oops_in_progress)
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@ -86,6 +86,7 @@ static int suspend_prepare(suspend_state_t state)
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goto Thaw;
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goto Thaw;
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}
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}
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suspend_console();
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if ((error = device_suspend(PMSG_SUSPEND))) {
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if ((error = device_suspend(PMSG_SUSPEND))) {
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printk(KERN_ERR "Some devices failed to suspend\n");
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printk(KERN_ERR "Some devices failed to suspend\n");
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goto Finish;
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goto Finish;
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@ -133,6 +134,7 @@ int suspend_enter(suspend_state_t state)
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static void suspend_finish(suspend_state_t state)
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static void suspend_finish(suspend_state_t state)
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{
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{
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device_resume();
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device_resume();
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resume_console();
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thaw_processes();
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thaw_processes();
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enable_nonboot_cpus();
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enable_nonboot_cpus();
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if (pm_ops && pm_ops->finish)
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if (pm_ops && pm_ops->finish)
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@ -67,6 +67,7 @@ EXPORT_SYMBOL(oops_in_progress);
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* driver system.
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* driver system.
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*/
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*/
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static DECLARE_MUTEX(console_sem);
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static DECLARE_MUTEX(console_sem);
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static DECLARE_MUTEX(secondary_console_sem);
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struct console *console_drivers;
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struct console *console_drivers;
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/*
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/*
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* This is used for debugging the mess that is the VT code by
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* This is used for debugging the mess that is the VT code by
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@ -76,7 +77,7 @@ struct console *console_drivers;
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* path in the console code where we end up in places I want
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* path in the console code where we end up in places I want
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* locked without the console sempahore held
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* locked without the console sempahore held
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*/
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*/
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static int console_locked;
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static int console_locked, console_suspended;
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/*
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/*
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* logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars
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* logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars
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@ -697,6 +698,23 @@ int __init add_preferred_console(char *name, int idx, char *options)
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return 0;
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return 0;
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}
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}
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/**
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* suspend_console - suspend the console subsystem
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*
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* This disables printk() while we go into suspend states
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*/
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void suspend_console(void)
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{
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acquire_console_sem();
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console_suspended = 1;
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}
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void resume_console(void)
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{
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console_suspended = 0;
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release_console_sem();
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}
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/**
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/**
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* acquire_console_sem - lock the console system for exclusive use.
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* acquire_console_sem - lock the console system for exclusive use.
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*
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*
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@ -708,6 +726,10 @@ int __init add_preferred_console(char *name, int idx, char *options)
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void acquire_console_sem(void)
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void acquire_console_sem(void)
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{
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{
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BUG_ON(in_interrupt());
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BUG_ON(in_interrupt());
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if (console_suspended) {
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down(&secondary_console_sem);
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return;
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}
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down(&console_sem);
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down(&console_sem);
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console_locked = 1;
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console_locked = 1;
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console_may_schedule = 1;
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console_may_schedule = 1;
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@ -750,6 +772,10 @@ void release_console_sem(void)
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unsigned long _con_start, _log_end;
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unsigned long _con_start, _log_end;
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unsigned long wake_klogd = 0;
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unsigned long wake_klogd = 0;
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if (console_suspended) {
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up(&secondary_console_sem);
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return;
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}
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for ( ; ; ) {
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for ( ; ; ) {
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spin_lock_irqsave(&logbuf_lock, flags);
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spin_lock_irqsave(&logbuf_lock, flags);
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wake_klogd |= log_start - log_end;
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wake_klogd |= log_start - log_end;
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