2 files changed, 16 insertions, 14 deletions

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 9eb3284deac4..99ebcd3884d2 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -586,7 +586,7 @@ void timer_interrupt(struct pt_regs * regs)
                 /* not time for this event yet */
                 now = per_cpu(decrementer_next_tb, cpu) - now;
                 if (now <= DECREMENTER_MAX)
-                        set_dec((unsigned int)now - 1);
+                        set_dec((int)now);
                 return;
         }
         old_regs = set_irq_regs(regs);
@@ -611,8 +611,6 @@ void timer_interrupt(struct pt_regs * regs)
 
         if (evt->event_handler)
                 evt->event_handler(evt);
-        else
-                evt->set_next_event(DECREMENTER_MAX, evt);
 
 #ifdef CONFIG_PPC_ISERIES
         if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending())
@@ -836,9 +834,6 @@ static int decrementer_set_next_event(unsigned long evt,
                                       struct clock_event_device *dev)
 {
         __get_cpu_var(decrementer_next_tb) = get_tb_or_rtc() + evt;
-        /* The decrementer interrupts on the 0 -> -1 transition */
-        if (evt)
-                --evt;
         set_dec(evt);
         return 0;
 }
@@ -871,7 +866,8 @@ void init_decrementer_clockevent(void)
                                              decrementer_clockevent.shift);
         decrementer_clockevent.max_delta_ns =
                 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
-        decrementer_clockevent.min_delta_ns = 1000;
+        decrementer_clockevent.min_delta_ns =
+                clockevent_delta2ns(2, &decrementer_clockevent);
 
         register_decrementer_clockevent(cpu);
 }
diff --git a/include/asm-powerpc/time.h b/include/asm-powerpc/time.h
index f05895522f7f..780f82642756 100644
--- a/include/asm-powerpc/time.h
+++ b/include/asm-powerpc/time.h
@@ -176,25 +176,31 @@ static inline unsigned int get_dec(void)
 #endif
 }
 
+/*
+ * Note: Book E and 4xx processors differ from other PowerPC processors
+ * in when the decrementer generates its interrupt: on the 1 to 0
+ * transition for Book E/4xx, but on the 0 to -1 transition for others.
+ */
 static inline void set_dec(int val)
 {
 #if defined(CONFIG_40x)
         mtspr(SPRN_PIT, val);
 #elif defined(CONFIG_8xx_CPU6)
-        set_dec_cpu6(val);
+        set_dec_cpu6(val - 1);
 #else
+#ifndef CONFIG_BOOKE
+        --val;
+#endif
 #ifdef CONFIG_PPC_ISERIES
-        int cur_dec;
-
         if (firmware_has_feature(FW_FEATURE_ISERIES) &&
                         get_lppaca()->shared_proc) {
                 get_lppaca()->virtual_decr = val;
-                cur_dec = get_dec();
-                if (cur_dec > val)
+                if (get_dec() > val)
                         HvCall_setVirtualDecr();
-        } else
+                return;
+        }
 #endif
-                mtspr(SPRN_DEC, val);
+        mtspr(SPRN_DEC, val);
 #endif /* not 40x or 8xx_CPU6 */
 }