Comment 3 for bug 632327

Not that I am suggesting a 'ready to use' solution, just my findings for more understanding ....
I can enable the option, but am not sure whether the recompiled kernel will suit my machine well ...

I see this on line no. 3275 in <linux-source-2.6.35>/debian.master/config/config.common.ubuntu
 # CONFIG_PM_ADVANCED_DEBUG is not set

and is used in <linux-source-2.6.35>/drivers/base/power/sysfs.c as
#ifdef CONFIG_PM_ADVANCED_DEBUG
#ifdef CONFIG_PM_RUNTIME

static ssize_t rtpm_usagecount_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
 return sprintf(buf, "%d\n", atomic_read(&dev->power.usage_count));
}

static ssize_t rtpm_children_show(struct device *dev,
      struct device_attribute *attr, char *buf)
{
 return sprintf(buf, "%d\n", dev->power.ignore_children ?
  0 : atomic_read(&dev->power.child_count));
}

static ssize_t rtpm_enabled_show(struct device *dev,
     struct device_attribute *attr, char *buf)
{
 if ((dev->power.disable_depth) && (dev->power.runtime_auto == false))
  return sprintf(buf, "disabled & forbidden\n");
 else if (dev->power.disable_depth)
  return sprintf(buf, "disabled\n");
 else if (dev->power.runtime_auto == false)
  return sprintf(buf, "forbidden\n");
 return sprintf(buf, "enabled\n");
}

static DEVICE_ATTR(runtime_usage, 0444, rtpm_usagecount_show, NULL);
static DEVICE_ATTR(runtime_active_kids, 0444, rtpm_children_show, NULL);
static DEVICE_ATTR(runtime_enabled, 0444, rtpm_enabled_show, NULL);

#endif