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Commit 4713e22c authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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clocksource: add unregister function to disable unusable clocksources 



On x86 the PIT might become an unusable clocksource. Add an unregister
function to provide a possibilty to remove the PIT from the list of
available clock sources.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 316da3b3

arch/x86/kernel/i8253.c

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <asm/delay.h>

#include <asm/i8253.h>

#include <asm/io.h>

#include <asm/hpet.h>



DEFINE_SPINLOCK(i8253_lock);

EXPORT_SYMBOL(i8253_lock);

include/linux/clocksource.h

+1 −0
Original line number Diff line number Diff line
@@ -215,6 +215,7 @@ static inline void clocksource_calculate_interval(struct clocksource *c, 


/* used to install a new clocksource */

extern int clocksource_register(struct clocksource*);

extern void clocksource_unregister(struct clocksource*);

extern struct clocksource* clocksource_get_next(void);

extern void clocksource_change_rating(struct clocksource *cs, int rating);

extern void clocksource_resume(void);

kernel/time/clocksource.c

+15 −0
Original line number Diff line number Diff line
@@ -337,6 +337,21 @@ void clocksource_change_rating(struct clocksource *cs, int rating) 
	spin_unlock_irqrestore(&clocksource_lock, flags);

}



/**

 * clocksource_unregister - remove a registered clocksource

 */

void clocksource_unregister(struct clocksource *cs)

{

	unsigned long flags;



	spin_lock_irqsave(&clocksource_lock, flags);

	list_del(&cs->list);

	if (clocksource_override == cs)

		clocksource_override = NULL;

	next_clocksource = select_clocksource();

	spin_unlock_irqrestore(&clocksource_lock, flags);

}



#ifdef CONFIG_SYSFS

/**

 * sysfs_show_current_clocksources - sysfs interface for current clocksource