x86: fix ioapic bug again

un-revert:

 commit 4960c9df1407c2723459c60ff13e6efe0c209c62
 Author: Thomas Gleixner <tglx@linutronix.de>
 Date:   Tue Jan 22 10:23:01 2008 +0100

     Revert "x86: fix NMI watchdog & 'stopped time' problem"

         This reverts commit d4d25deca49ec2527a634557bf5a6cf449f85deb.

needs a proper fix though ...

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 10 insertions, 2 deletions

diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index 742fab45e1c6..8ed6eb967652 100644
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -2124,10 +2124,14 @@ static inline void __init check_timer(void)
 {
         int apic1, pin1, apic2, pin2;
         int vector;
+        unsigned int ver;
         unsigned long flags;
 
         local_irq_save(flags);
 
+        ver = apic_read(APIC_LVR);
+        ver = GET_APIC_VERSION(ver);
+
         /*
          * get/set the timer IRQ vector:
          */
@@ -2140,11 +2144,15 @@ static inline void __init check_timer(void)
          * mode for the 8259A whenever interrupts are routed
          * through I/O APICs.  Also IRQ0 has to be enabled in
          * the 8259A which implies the virtual wire has to be
-         * disabled in the local APIC.
+         * disabled in the local APIC.  Finally timer interrupts
+         * need to be acknowledged manually in the 8259A for
+         * timer_interrupt() and for the i82489DX when using
+         * the NMI watchdog.
          */
         apic_write_around(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT);
         init_8259A(1);
-        timer_ack = 1;
+        timer_ack = !cpu_has_tsc;
+        timer_ack |= (nmi_watchdog == NMI_IO_APIC && !APIC_INTEGRATED(ver));
         if (timer_over_8254 > 0)
                 enable_8259A_irq(0);