Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d4d25deca49ec2527a634557bf5a6cf449f85deb
Commit:     d4d25deca49ec2527a634557bf5a6cf449f85deb
Parent:     2ffbb8377c7a0713baf6644e285adc27a5654582
Author:     Maciej W. Rozycki <[EMAIL PROTECTED]>
AuthorDate: Mon Nov 26 20:42:19 2007 +0100
Committer:  Ingo Molnar <[EMAIL PROTECTED]>
CommitDate: Mon Nov 26 20:42:19 2007 +0100

    x86: fix NMI watchdog & 'stopped time' problem
    
    More than 3 years ago Niclas Gustafsson reported a 'stopped time'
    problem:
    
    > Watching the /proc/interrupts with 10s apart after the "stop".
    >
    > [EMAIL PROTECTED] root]# more /proc/interrupts
    >            CPU0
    >   0:   66413955  local-APIC-edge  timer
    [...]
    > LOC:   67355837
    > ERR:          0
    > MIS:          0
    > [EMAIL PROTECTED] root]# more /proc/interrupts
    >            CPU0
    >   0:   66413955  local-APIC-edge  timer
    [...]
    > LOC:   67379568
    > ERR:          0
    > MIS:          0
    
    This may be because buggy SMM firmware messes with the 8259A (configured
    for a transparent mode -- yes that rare "local-APIC-edge" mode is tricky
    ;-) ) insanely.
    
    this should resolve:
    
      http://bugzilla.kernel.org/show_bug.cgi?id=2544
      http://bugzilla.kernel.org/show_bug.cgi?id=6296
    
    Patch-dusted-off-by: Ingo Molnar <[EMAIL PROTECTED]>
    Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
    Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
---
 arch/x86/kernel/io_apic_32.c |   12 ++++++++++--
 arch/x86/kernel/nmi_32.c     |    9 +++++++--
 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 f35c6eb..fc4bbc1 100644
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -2166,6 +2166,10 @@ static inline void __init check_timer(void)
 {
        int apic1, pin1, apic2, pin2;
        int vector;
+       unsigned int ver;
+
+       ver = apic_read(APIC_LVR);
+       ver = GET_APIC_VERSION(ver);
 
        /*
         * get/set the timer IRQ vector:
@@ -2179,11 +2183,15 @@ 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 600fd40..f5cc47c 100644
--- a/arch/x86/kernel/nmi_32.c
+++ b/arch/x86/kernel/nmi_32.c
@@ -25,6 +25,7 @@
 
 #include <asm/smp.h>
 #include <asm/nmi.h>
+#include <asm/timer.h>
 
 #include "mach_traps.h"
 
@@ -83,7 +84,7 @@ static 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 ... ");
 
@@ -117,7 +118,7 @@ static 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");
 
@@ -128,6 +129,10 @@ static int __init check_nmi_watchdog(void)
 
        kfree(prev_nmi_count);
        return 0;
+error:
+       timer_ack = !cpu_has_tsc;
+
+       return -1;
 }
 /* This needs to happen later in boot so counters are working */
 late_initcall(check_nmi_watchdog);
-
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