On Wed, 5 Mar 2008, Rafael J. Wysocki wrote:
> -void device_pm_add(struct device *dev)
> +int device_pm_add(struct device *dev)
> {
> + int error = 0;
> +
> pr_debug("PM: Adding info for %s:%s\n",
> dev->bus ? dev->bus->name : "No Bus",
> kobject_name(&dev->kobj));
> mutex_lock(&dpm_list_mtx);
> - list_add_tail(&dev->power.entry, &dpm_active);
> + if (dev->parent && dev->parent->power.sleeping) {
> + WARN_ON(true);
I would prefer to put a dev_warn() line here, so that people reading
the kernel log can easily tell which device caused the problem and what
sort of problem it is. Something like this:
dev_warn(dev, "device added while parent %s is asleep\n",
dev->parent->bus_id);
WARN_ON(true);
> @@ -426,6 +406,12 @@ static int dpm_suspend(pm_message_t stat
> struct list_head *entry = dpm_active.prev;
> struct device *dev = to_device(entry);
>
> + if (dev->parent && dev->parent->power.sleeping) {
> + WARN_ON(true);
> + error = -EAGAIN;
> + break;
Again, a dev_warn() would be appropriate.
And you might consider taking out the "error = -EAGAIN" and the
"break". When this occurs it doesn't mean that devices were suspended
in the wrong order; it means that the ordering of the parent pointers
fails to match the ordering of dpm_active. The only way for this to
happen is if the parent pointers are messed up by device_move() --
dpm_active will still be correct.
The rest of the patch looks fine.
Alan Stern
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