1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/acpi/acpica/hwtimer.c b/drivers/acpi/acpica/hwtimer.c
index bfdce22f3798..0c1a8bbd05d6 100644
--- a/drivers/acpi/acpica/hwtimer.c
+++ b/drivers/acpi/acpica/hwtimer.c
@@ -5,7 +5,7 @@
  *****************************************************************************/
 
 /*
- * Copyright (C) 2000 - 2012, Intel Corp.
+ * Copyright (C) 2000 - 2013, Intel Corp.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -176,10 +176,11 @@ acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
         /*
          * Compute Duration (Requires a 64-bit multiply and divide):
          *
-         * time_elapsed = (delta_ticks * 1000000) / PM_TIMER_FREQUENCY;
+         * time_elapsed (microseconds) =
+         *  (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
          */
-        status = acpi_ut_short_divide(((u64) delta_ticks) * 1000000,
-                                      PM_TIMER_FREQUENCY, &quotient, NULL);
+        status = acpi_ut_short_divide(((u64)delta_ticks) * ACPI_USEC_PER_SEC,
+                                      ACPI_PM_TIMER_FREQUENCY, &quotient, NULL);
 
         *time_elapsed = (u32) quotient;
         return_ACPI_STATUS(status);