4 files changed, 16 insertions, 1 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e39ab0c99fbb..09640a8f7ceb 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -780,6 +780,9 @@ 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
+                        C2 power state.
+
         lasi=           [HW,SCSI] PARISC LASI driver for the 53c700 chip
                         Format: addr:<io>,irq:<irq>
 
diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 244c3fe9b8c3..e88415282a6f 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -64,6 +64,9 @@ static int enable_local_apic __initdata = 0;
 static int local_apic_timer_verify_ok;
 /* Disable local APIC timer from the kernel commandline or via dmi quirk */
 static int local_apic_timer_disabled;
+/* Local APIC timer works in C2 */
+int local_apic_timer_c2_ok;
+EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
 
 /*
  * Debug level, exported for io_apic.c
@@ -1232,6 +1235,13 @@ static int __init parse_disable_lapic_timer(char *arg)
 }
 early_param("nolapic_timer", parse_disable_lapic_timer);
 
+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 int __init apic_set_verbosity(char *str)
 {
         if (strcmp("debug", str) == 0)
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 60773005b8af..cdf78943af4d 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -268,6 +268,7 @@ static void acpi_timer_check_state(int state, struct acpi_processor *pr,
                                    struct acpi_processor_cx *cx)
 {
         struct acpi_processor_power *pwr = &pr->power;
+        u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 
         /*
          * Check, if one of the previous states already marked the lapic
@@ -276,7 +277,7 @@ static void acpi_timer_check_state(int state, struct acpi_processor *pr,
         if (pwr->timer_broadcast_on_state < state)
                 return;
 
-        if (cx->type >= ACPI_STATE_C2)
+        if (cx->type >= type)
                 pr->power.timer_broadcast_on_state = state;
 }
 
diff --git a/include/asm-i386/apic.h b/include/asm-i386/apic.h
index cc6b1652249a..a19810a08ae9 100644
--- a/include/asm-i386/apic.h
+++ b/include/asm-i386/apic.h
@@ -117,6 +117,7 @@ extern void enable_NMI_through_LVT0 (void * dummy);
 #define ARCH_APICTIMER_STOPS_ON_C3      1
 
 extern int timer_over_8254;
+extern int local_apic_timer_c2_ok;
 
 #else /* !CONFIG_X86_LOCAL_APIC */
 static inline void lapic_shutdown(void) { }