[PATCH] x86_64: 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 x86_64.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 43c9fa0f8d5f..211bf0e51d9d 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -471,6 +471,11 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
  
         write_sequnlock(&xtime_lock);
 
+#ifdef CONFIG_X86_LOCAL_APIC
+        if (using_apic_timer)
+                smp_send_timer_broadcast_ipi();
+#endif
+
         return IRQ_HANDLED;
 }