5 files changed, 12 insertions, 1 deletions

diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 2eeaa95edff0..7392570f975d 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -917,6 +917,8 @@ void __init time_init(void)
                 vxtime.hpet_address = 0;
 
         if (hpet_use_timer) {
+                /* set tick_nsec to use the proper rate for HPET */
+                tick_nsec = TICK_NSEC_HPET;
                 cpu_khz = hpet_calibrate_tsc();
                 timename = "HPET";
 #ifdef CONFIG_X86_PM_TIMER
diff --git a/include/asm-i386/hpet.h b/include/asm-i386/hpet.h
index 16ef9f996e3f..7f1a8a6ee32f 100644
--- a/include/asm-i386/hpet.h
+++ b/include/asm-i386/hpet.h
@@ -89,6 +89,7 @@
  * then 32 bit HPET counter wrapsaround in less than 0.5 sec.
  */
 #define HPET_MIN_PERIOD (100000UL)
+#define HPET_TICK_RATE  (HZ * 100000UL)
 
 extern unsigned long hpet_tick;         /* hpet clks count per tick */
 extern unsigned long hpet_address;      /* hpet memory map physical address */
diff --git a/include/asm-x86_64/hpet.h b/include/asm-x86_64/hpet.h
index 08b75c15269a..18ff7ee9e774 100644
--- a/include/asm-x86_64/hpet.h
+++ b/include/asm-x86_64/hpet.h
@@ -51,6 +51,8 @@
 
 #define HPET_TN_ROUTE_SHIFT     9
 
+#define HPET_TICK_RATE (HZ * 100000UL)
+
 extern int is_hpet_enabled(void);
 extern int hpet_rtc_timer_init(void);
 extern int oem_force_hpet_timer(void);
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 99905e180532..043376920f51 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -36,6 +36,8 @@
 /* LATCH is used in the interval timer and ftape setup. */
 #define LATCH  ((CLOCK_TICK_RATE + HZ/2) / HZ)  /* For divider */
 
+#define LATCH_HPET ((HPET_TICK_RATE + HZ/2) / HZ)
+
 /* Suppose we want to devide two numbers NOM and DEN: NOM/DEN, the we can
  * improve accuracy by shifting LSH bits, hence calculating:
  *     (NOM << LSH) / DEN
@@ -51,9 +53,13 @@
 /* HZ is the requested value. ACTHZ is actual HZ ("<< 8" is for accuracy) */
 #define ACTHZ (SH_DIV (CLOCK_TICK_RATE, LATCH, 8))
 
+#define ACTHZ_HPET (SH_DIV (HPET_TICK_RATE, LATCH_HPET, 8))
+
 /* TICK_NSEC is the time between ticks in nsec assuming real ACTHZ */
 #define TICK_NSEC (SH_DIV (1000000UL * 1000, ACTHZ, 8))
 
+#define TICK_NSEC_HPET (SH_DIV(1000000UL * 1000, ACTHZ_HPET, 8))
+
 /* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */
 #define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ)
 
diff --git a/kernel/timer.c b/kernel/timer.c
index c3a874f1393c..471ab8710b8f 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1455,7 +1455,7 @@ static void time_interpolator_update(long delta_nsec)
          */
         if (jiffies % INTERPOLATOR_ADJUST == 0)
         {
-                if (time_interpolator->skips == 0 && time_interpolator->offset > TICK_NSEC)
+                if (time_interpolator->skips == 0 && time_interpolator->offset > tick_nsec)
                         time_interpolator->nsec_per_cyc--;
                 if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0)
                         time_interpolator->nsec_per_cyc++;