x86: I/O APIC: clean up the 8259A on a NMI watchdog failure

There is no point in keeping the 8259A enabled if the I/O APIC NMI
watchdog has failed and the 8259A is not used to pass through regular
timer interrupts.  This fixes problems with some systems where some logic
gets confused.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index aa45a85c4d11..2a60bfb7446f 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -90,6 +90,7 @@ static int no_timer_check;
 
 static int disable_timer_pin_1 __initdata;
 
+int timer_through_8259 __initdata;
 
 /* Where if anywhere is the i8259 connect in external int mode */
 static struct { int pin, apic; } ioapic_i8259 = { -1, -1 };
@@ -1700,6 +1701,7 @@ static inline void __init check_timer(void)
                 enable_8259A_irq(0);
                 if (timer_irq_works()) {
                         apic_printk(APIC_VERBOSE," works.\n");
+                        timer_through_8259 = 1;
                         nmi_watchdog_default();
                         if (nmi_watchdog == NMI_IO_APIC) {
                                 disable_8259A_irq(0);