1 files changed, 32 insertions, 2 deletions

diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index 5d3c5b07b8db..14751dda7dcf 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -35,8 +35,11 @@
 #include <asm/mach_apic.h>
 #include <asm/nmi.h>
 #include <asm/idle.h>
+#include <asm/proto.h>
+#include <asm/timex.h>
 
 int apic_verbosity;
+int apic_runs_main_timer;
 
 int disable_apic_timer __initdata;
 
@@ -702,9 +705,17 @@ static void setup_APIC_timer(unsigned int clocks)
                         c2 |= inb_p(0x40) << 8;
                 } while (c2 - c1 < 300);
         }
-
         __setup_APIC_LVTT(clocks);
-
+        /* Turn off PIT interrupt if we use APIC timer as main timer.
+           Only works with the PM timer right now
+           TBD fix it for HPET too. */
+        if (vxtime.mode == VXTIME_PMTMR &&
+                smp_processor_id() == boot_cpu_id &&
+                apic_runs_main_timer == 1 &&
+                !cpu_isset(boot_cpu_id, timer_interrupt_broadcast_ipi_mask)) {
+                stop_timer_interrupt();
+                apic_runs_main_timer++;
+        }
         local_irq_restore(flags);
 }
 
@@ -872,6 +883,8 @@ void smp_local_timer_interrupt(struct pt_regs *regs)
 #ifdef CONFIG_SMP
         update_process_times(user_mode(regs));
 #endif
+        if (apic_runs_main_timer > 1 && smp_processor_id() == boot_cpu_id)
+                main_timer_handler(regs);
         /*
          * We take the 'long' return path, and there every subsystem
          * grabs the appropriate locks (kernel lock/ irq lock).
@@ -1081,10 +1094,27 @@ static __init int setup_nolapic(char *str)
 
 static __init int setup_noapictimer(char *str) 
 { 
+        if (str[0] != ' ' && str[0] != 0)
+                return -1;
         disable_apic_timer = 1;
         return 0;
 } 
 
+static __init int setup_apicmaintimer(char *str)
+{
+        apic_runs_main_timer = 1;
+        nohpet = 1;
+        return 0;
+}
+__setup("apicmaintimer", setup_apicmaintimer);
+
+static __init int setup_noapicmaintimer(char *str)
+{
+        apic_runs_main_timer = -1;
+        return 0;
+}
+__setup("noapicmaintimer", setup_noapicmaintimer);
+
 /* dummy parsing: see setup.c */
 
 __setup("disableapic", setup_disableapic);