Revert "Revert "x86: fix ioapic bug again""

This reverts commit 0b6a39f7ebcb1c82587ce35b401c513eed41ac5c.

The changes in tip/x86/apic solve this better.

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

2 files changed, 17 insertions, 4 deletions

diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index 4dc8600d9d20..a40d54fc1fdd 100644
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -2130,10 +2130,14 @@ 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:
          */
@@ -2146,11 +2150,15 @@ 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);
 
diff --git a/arch/x86/kernel/nmi_32.c b/arch/x86/kernel/nmi_32.c
index 84160f74eeb0..11b14bbaa61e 100644
--- a/arch/x86/kernel/nmi_32.c
+++ b/arch/x86/kernel/nmi_32.c
@@ -26,6 +26,7 @@
 
 #include <asm/smp.h>
 #include <asm/nmi.h>
+#include <asm/timer.h>
 
 #include "mach_traps.h"
 
@@ -81,7 +82,7 @@ int __init check_nmi_watchdog(void)
 
         prev_nmi_count = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL);
         if (!prev_nmi_count)
-                return -1;
+                goto error;
 
         printk(KERN_INFO "Testing NMI watchdog ... ");
 
@@ -118,7 +119,7 @@ int __init check_nmi_watchdog(void)
         if (!atomic_read(&nmi_active)) {
                 kfree(prev_nmi_count);
                 atomic_set(&nmi_active, -1);
-                return -1;
+                goto error;
         }
         printk("OK.\n");
 
@@ -129,6 +130,10 @@ int __init check_nmi_watchdog(void)
 
         kfree(prev_nmi_count);
         return 0;
+error:
+        timer_ack = !cpu_has_tsc;
+
+        return -1;
 }
 
 static int __init setup_nmi_watchdog(char *str)