3 files changed, 13 insertions, 1 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 09640a8f7ceb..ef2ffded1392 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -780,7 +780,7 @@ and is between 256 and 4096 characters. It is defined in the file
         lapic           [IA-32,APIC] Enable the local APIC even if BIOS
                         disabled it.
 
-        lapic_timer_c2_ok       [IA-32,APIC] trust the local apic timer in
+        lapic_timer_c2_ok       [IA-32,x86-64,APIC] trust the local apic timer in
                         C2 power state.
 
         lasi=           [HW,SCSI] PARISC LASI driver for the 53c700 chip
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index 723417d924c0..46acf4f2f1ec 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -47,6 +47,10 @@ int apic_calibrate_pmtmr __initdata;
 
 int disable_apic_timer __initdata;
 
+/* Local APIC timer works in C2? */
+int local_apic_timer_c2_ok;
+EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
+
 static struct resource *ioapic_resources;
 static struct resource lapic_resource = {
         .name = "Local APIC",
@@ -1192,6 +1196,13 @@ static __init int setup_nolapic(char *str)
 } 
 early_param("nolapic", setup_nolapic);
 
+static int __init parse_lapic_timer_c2_ok(char *arg)
+{
+        local_apic_timer_c2_ok = 1;
+        return 0;
+}
+early_param("lapic_timer_c2_ok", parse_lapic_timer_c2_ok);
+
 static __init int setup_noapictimer(char *str) 
 { 
         if (str[0] != ' ' && str[0] != 0)
diff --git a/include/asm-x86_64/apic.h b/include/asm-x86_64/apic.h
index e81d0f289f0b..7cfb39cbd918 100644
--- a/include/asm-x86_64/apic.h
+++ b/include/asm-x86_64/apic.h
@@ -102,5 +102,6 @@ void switch_ipi_to_APIC_timer(void *cpumask);
 #define ARCH_APICTIMER_STOPS_ON_C3      1
 
 extern unsigned boot_cpu_id;
+extern int local_apic_timer_c2_ok;
 
 #endif /* __ASM_APIC_H */