ACPI: C-States: bm_activity improvements

Do not assume there was bus mastering activity if the idle handler didn't get
called, as there's only reason to not enter C3-type sleep if there is bus
master activity going on.  Only for the "promotion" into C3-type sleep bus
mastering activity is taken into account, and there only current bus mastering
activity, and not pure guessing should lead to the decision on whether to
enter C3-type sleep or not.

Also, as bm_activity is a jiffy-based bitmask (bit 0: bus mastering activity
during this juffy, bit 31: bus mastering activity 31 jiffies ago), fix the
setting of bit 0, as it might be called multiple times within one jiffy.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 6 insertions, 12 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 6d1e238e2375..af9f2afd72da 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;