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Commit e17bcb43 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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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: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Acked-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
parent 167b1de3

drivers/acpi/processor_idle.c

+14 −5
Original line number Diff line number Diff line
@@ -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);