diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 6d1e238e2375107987c109b24df0c28464ee6da1..af9f2afd72da458abb51bd520034b0fe2987dad4 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -3,7 +3,7 @@
  *
  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
- *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
+ *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
  *  			- Added processor hotplug support
  *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
@@ -261,21 +261,15 @@ static void acpi_processor_idle(void)
 		u32 bm_status = 0;
 		unsigned long diff = jiffies - pr->power.bm_check_timestamp;
 
-		if (diff > 32)
-			diff = 32;
+		if (diff > 31)
+			diff = 31;
 
-		while (diff) {
-			/* if we didn't get called, assume there was busmaster activity */
-			diff--;
-			if (diff)
-				pr->power.bm_activity |= 0x1;
-			pr->power.bm_activity <<= 1;
-		}
+		pr->power.bm_activity <<= diff;
 
 		acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
 				  &bm_status, ACPI_MTX_DO_NOT_LOCK);
 		if (bm_status) {
-			pr->power.bm_activity++;
+			pr->power.bm_activity |= 0x1;
 			acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
 					  1, ACPI_MTX_DO_NOT_LOCK);
 		}
@@ -287,7 +281,7 @@ static void acpi_processor_idle(void)
 		else if (errata.piix4.bmisx) {
 			if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 			    || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
-				pr->power.bm_activity++;
+				pr->power.bm_activity |= 0x1;
 		}
 
 		pr->power.bm_check_timestamp = jiffies;