[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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index e34af77..4ea6d8b 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -248,6 +248,48 @@
}
}
+#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 @@
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 @@
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 @@
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);
}