ACPI: move timer broadcast before busmaster disable

The timer broadcast code might access HPET, which should not be
accessed after the busmaster disable.

In acpi_idle_enter_simple() this change also prevents, that we modify
the busmaster state without going actually idle. This might leave the
ACPI bm state in a stale state, when we leave the function early in
the need_resched() check.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>

1 files changed, 14 insertions, 5 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index b1fbee3f7fe1..2fe34cc73c13 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -531,6 +531,11 @@ static void acpi_processor_idle(void)
 
         case ACPI_STATE_C3:
                 /*
+                 * Must be done before busmaster disable as we might
+                 * need to access HPET !
+                 */
+                acpi_state_timer_broadcast(pr, cx, 1);
+                /*
                  * disable bus master
                  * bm_check implies we need ARB_DIS
                  * !bm_check implies we need cache flush
@@ -557,7 +562,6 @@ static void acpi_processor_idle(void)
                 /* Get start time (ticks) */
                 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
                 /* Invoke C3 */
-                acpi_state_timer_broadcast(pr, cx, 1);
                 /* Tell the scheduler that we are going deep-idle: */
                 sched_clock_idle_sleep_event();
                 acpi_cstate_enter(cx);
@@ -1401,9 +1405,6 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
         if (acpi_idle_suspend)
                 return(acpi_idle_enter_c1(dev, state));
 
-        if (pr->flags.bm_check)
-                acpi_idle_update_bm_rld(pr, cx);
-
         local_irq_disable();
         current_thread_info()->status &= ~TS_POLLING;
         /*
@@ -1418,13 +1419,21 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
                 return 0;
         }
 
+        /*
+         * Must be done before busmaster disable as we might need to
+         * access HPET !
+         */
+        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();
 
         t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
         /* Tell the scheduler that we are going deep-idle: */
         sched_clock_idle_sleep_event();
-        acpi_state_timer_broadcast(pr, cx, 1);
         acpi_idle_do_entry(cx);
         t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);