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Commit 169a0abb authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds
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[PATCH] ACPI keep track of timer broadcasting 



This is a preperatory patch for highres/dyntick:

- replace the big #ifdef ARCH_APICTIMER_STOPS_ON_C3 hackery by functions

- remove the double switch in the power verify function (in the worst case
  we switched ipi to apic and 20usec later apic to ipi)

- keep track of the the state which stops local APIC timer

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: Len Brown <len.brown@intel.com>
Cc: <linux-acpi@vger.kernel.org>
Cc: Andi Kleen <ak@suse.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3434933b

drivers/acpi/processor_idle.c

+47 −19
Original line number Diff line number Diff line
@@ -248,6 +248,48 @@ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) 
	}

}



#ifdef ARCH_APICTIMER_STOPS_ON_C3



/*

 * Some BIOS implementations switch to C3 in the published C2 state.

 * This seems to be a common problem on AMD boxen, but other vendors

 * are affected too. We pick the most conservative approach: we assume

 * that the local APIC stops in both C2 and C3.

 */

static void acpi_timer_check_state(int state, struct acpi_processor *pr,

				   struct acpi_processor_cx *cx)

{

	struct acpi_processor_power *pwr = &pr->power;



	/*

	 * Check, if one of the previous states already marked the lapic

	 * unstable

	 */

	if (pwr->timer_broadcast_on_state < state)

		return;



	if (cx->type >= ACPI_STATE_C2)

		pr->power.timer_broadcast_on_state = state;

}



static void acpi_propagate_timer_broadcast(struct acpi_processor *pr)

{

	cpumask_t mask = cpumask_of_cpu(pr->id);



	if (pr->power.timer_broadcast_on_state < INT_MAX)

		on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);

	else

		on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);

}



#else



static void acpi_timer_check_state(int state, struct acpi_processor *pr,

				   struct acpi_processor_cx *cstate) { }

static void acpi_propagate_timer_broadcast(struct acpi_processor *pr) { }



#endif



static void acpi_processor_idle(void)

{

	struct acpi_processor *pr = NULL;
@@ -914,11 +956,7 @@ static int acpi_processor_power_verify(struct acpi_processor *pr) 
	unsigned int i;

	unsigned int working = 0;



#ifdef ARCH_APICTIMER_STOPS_ON_C3

	int timer_broadcast = 0;

	cpumask_t mask = cpumask_of_cpu(pr->id);

	on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);

#endif

	pr->power.timer_broadcast_on_state = INT_MAX;



	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {

		struct acpi_processor_cx *cx = &pr->power.states[i];
@@ -930,21 +968,14 @@ static int acpi_processor_power_verify(struct acpi_processor *pr) 


		case ACPI_STATE_C2:

			acpi_processor_power_verify_c2(cx);

#ifdef ARCH_APICTIMER_STOPS_ON_C3

			/* Some AMD systems fake C3 as C2, but still

			   have timer troubles */

			if (cx->valid && 

				boot_cpu_data.x86_vendor == X86_VENDOR_AMD)

				timer_broadcast++;

#endif

			if (cx->valid)

				acpi_timer_check_state(i, pr, cx);

			break;



		case ACPI_STATE_C3:

			acpi_processor_power_verify_c3(pr, cx);

#ifdef ARCH_APICTIMER_STOPS_ON_C3

			if (cx->valid)

				timer_broadcast++;

#endif

				acpi_timer_check_state(i, pr, cx);

			break;

		}
@@ -952,10 +983,7 @@ static int acpi_processor_power_verify(struct acpi_processor *pr) 
			working++;

	}



#ifdef ARCH_APICTIMER_STOPS_ON_C3

	if (timer_broadcast)

		on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);

#endif

	acpi_propagate_timer_broadcast(pr);



	return (working);

}

include/acpi/processor.h

+1 −0
Original line number Diff line number Diff line
@@ -79,6 +79,7 @@ struct acpi_processor_power { 
	u32 bm_activity;

	int count;

	struct acpi_processor_cx states[ACPI_PROCESSOR_MAX_POWER];

	int timer_broadcast_on_state;

};



/* Performance Management */