Comment 18 for bug 9185

I had the same problem on a VIA chipset, Abit VA-10.
It seems that the problem is due to the kernel patch which is applied for fixing
the same problem on IBM T42 machines.
I cannot find anymore the Ubuntu bugzilla bug on which the fix for the T42 is
accepted.
But this is the patch, the two lines that it adds break poweroff on my VA-10:

--- linux-2.6.7.bak/drivers/acpi/sleep/poweroff.c 2004-06-16 07:20:04.000000000
+0200
+++ linux-2.6.7/drivers/acpi/sleep/poweroff.c 2004-06-17 19:44:49.000000000 +0200
@@ -9,11 +9,13 @@
 #include <linux/init.h>
 #include <acpi/acpi_bus.h>
 #include <linux/sched.h>
+#include <asm/apic.h>

 static void
 acpi_power_off (void)
 {
  printk("%s called\n",__FUNCTION__);
+ disable_local_APIC ();
  /* Some SMP machines only can poweroff in boot CPU */
  set_cpus_allowed(current, cpumask_of_cpu(0));
  acpi_enter_sleep_state_prep(ACPI_STATE_S5);