The PC-speaker code has a quite creative method to serialize access to the PIT: It uses a local lock.
On i386 and x86_64 the access to the PIT is serialized by a lock in the architecture code. The separate locking in the PC-speaker code ignores the global lock and creates a nasty race between the PC-speaker and the PIT clock source / events code on SMP machines. Use the global i8253_lock instead of the local i8253_beep_lock, when compiled for i386/x86_64. Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]> Index: linux-2.6/arch/x86_64/kernel/time.c =================================================================== --- linux-2.6.orig/arch/x86_64/kernel/time.c +++ linux-2.6/arch/x86_64/kernel/time.c @@ -33,6 +33,7 @@ #include <acpi/acpi_bus.h> #endif #include <asm/8253pit.h> +#include <asm/i8253.h> #include <asm/pgtable.h> #include <asm/vsyscall.h> #include <asm/timex.h> @@ -50,6 +51,7 @@ static char *timename = NULL; DEFINE_SPINLOCK(rtc_lock); EXPORT_SYMBOL(rtc_lock); DEFINE_SPINLOCK(i8253_lock); +EXPORT_SYMBOL(i8253_lock); volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES; Index: linux-2.6/drivers/input/misc/pcspkr.c =================================================================== --- linux-2.6.orig/drivers/input/misc/pcspkr.c +++ linux-2.6/drivers/input/misc/pcspkr.c @@ -24,7 +24,12 @@ MODULE_AUTHOR("Vojtech Pavlik <[EMAIL PROTECTED] MODULE_DESCRIPTION("PC Speaker beeper driver"); MODULE_LICENSE("GPL"); -static DEFINE_SPINLOCK(i8253_beep_lock); +#ifdef CONFIG_X86 +/* Use the global PIT lock ! */ +#include <asm/i8253.h> +#else +static DEFINE_SPINLOCK(i8253_lock); +#endif static int pcspkr_event(struct input_dev *dev, unsigned int type, unsigned int code, int value) { @@ -43,7 +48,7 @@ static int pcspkr_event(struct input_dev if (value > 20 && value < 32767) count = PIT_TICK_RATE / value; - spin_lock_irqsave(&i8253_beep_lock, flags); + spin_lock_irqsave(&i8253_lock, flags); if (count) { /* enable counter 2 */ @@ -58,7 +63,7 @@ static int pcspkr_event(struct input_dev outb(inb_p(0x61) & 0xFC, 0x61); } - spin_unlock_irqrestore(&i8253_beep_lock, flags); + spin_unlock_irqrestore(&i8253_lock, flags); return 0; } Index: linux-2.6/include/asm-x86_64/i8253.h =================================================================== --- /dev/null +++ linux-2.6/include/asm-x86_64/i8253.h @@ -0,0 +1,6 @@ +#ifndef __ASM_I8253_H__ +#define __ASM_I8253_H__ + +extern spinlock_t i8253_lock; + +#endif /* __ASM_I8253_H__ */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/