[PATCH] x86_64: Only switch to IPI broadcast timer on Intel when C3 is supported

Bug in apic timer removal on C3 patch. We should switch to IPI from APIC timer
only when C3 state is valid.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/acpi/processor_idle.c

@@ -899,7 +899,7 @@ static int acpi_processor_power_verify(struct acpi_processor *pr)
 		case ACPI_STATE_C3:
 			acpi_processor_power_verify_c3(pr, cx);
 #ifdef ARCH_APICTIMER_STOPS_ON_C3
-			if (c->x86_vendor == X86_VENDOR_INTEL) {
+			if (cx->valid && c->x86_vendor == X86_VENDOR_INTEL) {
 				on_each_cpu(switch_APIC_timer_to_ipi,
 						&mask, 1, 1);
 			}