i386,x86-64 (take 2) Handle missing local APIC timer interrupts on C3 state

PATCH In review Venkatesh Pallipadi 1 participant 2 messages Dec 13, 2005 ACPI

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Venkatesh Pallipadi

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2005-12-13 01:49 UTC #0 lore raw

PATCH 2/3 i386,x86-64 (take 2) Handle missing local APIC timer interrupts on C3 state

Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we disable local APIC timer and switch to using a broadcast from external timer interrupt (IRQ 0).

Patch below adds the code for i386 and also the ACPI hunk.

Signed-off-by Venkatesh Pallipadi <[email protected]>

arch/i386/kernel/time.c +6 -0

Index: linux-2.6.15-rc3/arch/i386/kernel/time.c
===================================================================
@@ -302,6 +302,12 @@ irqreturn_t timer_interrupt(int irq, voi
 	do_timer_interrupt(irq, regs);
 
 	write_sequnlock(&xtime_lock);
+
+#ifdef CONFIG_X86_LOCAL_APIC
+	if (using_apic_timer)
+		smp_send_timer_broadcast_ipi(regs);
+#endif
+
 	return IRQ_HANDLED;
 }

include/asm-i386/apic.h +5 -0

Index: linux-2.6.15-rc3/include/asm-i386/apic.h
===================================================================
@@ -132,6 +132,11 @@ extern unsigned int nmi_watchdog;
 
 extern int disable_timer_pin_1;
 
+void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
+void switch_APIC_timer_to_ipi(void *cpumask);
+void switch_ipi_to_APIC_timer(void *cpumask);
+#define ARCH_APICTIMER_STOPS_ON_C3	1
+
 #else /* !CONFIG_X86_LOCAL_APIC */
 static inline void lapic_shutdown(void) { }

arch/i386/kernel/apic.c +76 -2

129 lines not on this page · raw message

drivers/acpi/processor_idle.c +15 -0

Index: linux-2.6.15-rc3/drivers/acpi/processor_idle.c
===================================================================
@@ -929,6 +929,15 @@ static int acpi_processor_power_verify(s
 	unsigned int i;
 	unsigned int working = 0;
 
+#ifdef ARCH_APICTIMER_STOPS_ON_C3
+	struct cpuinfo_x86 *c = cpu_data + pr->id;
+	cpumask_t mask = cpumask_of_cpu(pr->id);
+
+	if (c->x86_vendor == X86_VENDOR_INTEL) {
+		on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
+	}
+#endif
+
 	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 		struct acpi_processor_cx *cx = &pr->power.states[i];

@@ -943,6 +952,12 @@ static int acpi_processor_power_verify(s
 
 		case ACPI_STATE_C3:
 			acpi_processor_power_verify_c3(pr, cx);
+#ifdef ARCH_APICTIMER_STOPS_ON_C3
+			if (c->x86_vendor == X86_VENDOR_INTEL) {
+				on_each_cpu(switch_APIC_timer_to_ipi, 
+						&mask, 1, 1);
+			}
+#endif
 			break;
 		}