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>

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index b1fbee3..2fe34cc 100644 (file)
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -530,6 +530,11 @@ static void acpi_processor_idle(void)
                break;
 
        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
@@ -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);