1 files changed, 9 insertions, 48 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index ae0010821ce3..7eab733ae96e 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -241,26 +241,6 @@ acpi_processor_power_activate(struct acpi_processor *pr,
                 old->promotion.count = 0;
         new->demotion.count = 0;
 
-        /* Cleanup from old state. */
-        if (old) {
-                switch (old->type) {
-                case ACPI_STATE_C3:
-                        /* Disable bus master reload */
-                        if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
-                                acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
-                        break;
-                }
-        }
-
-        /* Prepare to use new state. */
-        switch (new->type) {
-        case ACPI_STATE_C3:
-                /* Enable bus master reload */
-                if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
-                        acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
-                break;
-        }
-
         pr->power.state = new;
 
         return;
@@ -1121,7 +1101,6 @@ static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
                                           " for C3 to be enabled on SMP systems\n"));
                         return;
                 }
-                acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
         }
 
         /*
@@ -1137,6 +1116,15 @@ static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 #else
         cx->latency_ticks = cx->latency;
 #endif
+        /*
+         * On older chipsets, BM_RLD needs to be set
+         * in order for Bus Master activity to wake the
+         * system from C3.  Newer chipsets handle DMA
+         * during C3 automatically and BM_RLD is a NOP.
+         * In either case, the proper way to
+         * handle BM_RLD is to set it and leave it set.
+         */
+        acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 
         return;
 }
@@ -1400,25 +1388,6 @@ static int acpi_idle_bm_check(void)
 }
 
 /**
- * acpi_idle_update_bm_rld - updates the BM_RLD bit depending on target state
- * @pr: the processor
- * @target: the new target state
- */
-static inline void acpi_idle_update_bm_rld(struct acpi_processor *pr,
-                                           struct acpi_processor_cx *target)
-{
-        if (pr->flags.bm_rld_set && target->type != ACPI_STATE_C3) {
-                acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
-                pr->flags.bm_rld_set = 0;
-        }
-
-        if (!pr->flags.bm_rld_set && target->type == ACPI_STATE_C3) {
-                acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
-                pr->flags.bm_rld_set = 1;
-        }
-}
-
-/**
  * acpi_idle_do_entry - a helper function that does C2 and C3 type entry
  * @cx: cstate data
  *
@@ -1473,9 +1442,6 @@ static int acpi_idle_enter_c1(struct cpuidle_device *dev,
                 return 0;
         }
 
-        if (pr->flags.bm_check)
-                acpi_idle_update_bm_rld(pr, cx);
-
         t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
         acpi_idle_do_entry(cx);
         t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
@@ -1527,9 +1493,6 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
          */
         acpi_state_timer_broadcast(pr, cx, 1);
 
-        if (pr->flags.bm_check)
-                acpi_idle_update_bm_rld(pr, cx);
-
         if (cx->type == ACPI_STATE_C3)
                 ACPI_FLUSH_CPU_CACHE();
 
@@ -1621,8 +1584,6 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
          */
         acpi_state_timer_broadcast(pr, cx, 1);
 
-        acpi_idle_update_bm_rld(pr, cx);
-
         /*
          * disable bus master
          * bm_check implies we need ARB_DIS