Index: acpi_cpu.c
===================================================================
RCS file: /home/source/dragonfly/cvs/src/sys/dev/acpica5/acpi_cpu.c,v
retrieving revision 1.19
diff -u -p -r1.19 acpi_cpu.c
--- acpi_cpu.c	22 Feb 2007 04:02:50 -0000	1.19
+++ acpi_cpu.c	24 Feb 2007 11:07:43 -0000
@@ -182,10 +182,15 @@ static devclass_t acpi_cpu_devclass;
 DRIVER_MODULE(cpu, acpi, acpi_cpu_driver, acpi_cpu_devclass, 0, 0);
 MODULE_DEPEND(cpu, acpi, 1, 1, 1);
 
+static int acpi_cpu_probe_debug_knob = 0;
+TUNABLE_INT("debug.acpi.cpu.knob", &acpi_cpu_probe_debug_knob);
+#define DEBUG_KNOB(n)	\
+    if (acpi_cpu_probe_debug_knob == (n)) return(ENXIO)
+
 static int
 acpi_cpu_probe(device_t dev)
 {
-    int			   acpi_id, cpu_id, cx_count;
+    int			   acpi_id, cpu_id, proc_id, cx_count;
     ACPI_BUFFER		   buf;
     ACPI_HANDLE		   handle;
     char		   msg[32];
@@ -196,14 +201,16 @@ acpi_cpu_probe(device_t dev)
 	return (ENXIO);
 
     handle = acpi_get_handle(dev);
+DEBUG_KNOB(1);
     if (cpu_softc == NULL)
 	cpu_softc = kmalloc(sizeof(struct acpi_cpu_softc *) *
 	    SMP_MAXCPU, M_TEMP /* XXX */, M_INTWAIT | M_ZERO);
-
+DEBUG_KNOB(2);
     /* Get our Processor object. */
     buf.Pointer = NULL;
     buf.Length = ACPI_ALLOCATE_BUFFER;
     status = AcpiEvaluateObject(handle, NULL, NULL, &buf);
+DEBUG_KNOB(3);
     if (ACPI_FAILURE(status)) {
 	device_printf(dev, "probe failed to get Processor obj - %s\n",
 		      AcpiFormatException(status));
@@ -221,18 +228,25 @@ acpi_cpu_probe(device_t dev)
      * ProcId as a key, however, some boxes do not have the same values
      * in their Processor object as the ProcId values in the MADT.
      */
-    acpi_id = obj->Processor.ProcId;
+    acpi_id = proc_id = obj->Processor.ProcId;
     AcpiOsFree(obj);
-    if (acpi_pcpu_get_id(device_get_unit(dev), &acpi_id, &cpu_id) != 0)
+DEBUG_KNOB(4);
+    if (acpi_pcpu_get_id(device_get_unit(dev), &acpi_id, &cpu_id) != 0) {
+	if (bootverbose)
+	    device_printf(dev, "ProcId %d: can't find cpu_id\n", proc_id);
 	return (ENXIO);
-
+    }
+    if (bootverbose) {
+	device_printf(dev, "ProcId %d: acpi_id=%d, cpu_id=%d\n", proc_id,
+		      acpi_id, cpu_id);
+    }
     /*
      * Check if we already probed this processor.  We scan the bus twice
      * so it's possible we've already seen this one.
      */
     if (cpu_softc[cpu_id] != NULL)
 	return (ENXIO);
-
+DEBUG_KNOB(5);
     /* Get a count of Cx states for our device string. */
     cx_count = 0;
     buf.Pointer = NULL;
@@ -263,6 +277,7 @@ acpi_cpu_probe(device_t dev)
 
     return (0);
 }
+#undef DEBUG_KNOB
 
 static int
 acpi_cpu_attach(device_t dev)