On Wed, 20 Feb 2008, Rafael J. Wysocki wrote:

quoted text
> Well, below is an uncompiled and untested but illustrating the idea that
> might allow people not to bother with device_pm_schedule_removal()
> explicitly and can fix the issue at hand.
> 
> [There are some cases that need handling and are not covered here.]
> 
> Please have a look.
> 
> Thanks,
> Rafael

quoted text
> +static struct task_struct *suspending_task;
> +static DEFINE_MUTEX(suspending_task_mtx);

I suspect you don't really need this mutex.

quoted text
> +bool in_suspend_context(void)
> +{
> +	bool result;
> +
> +	mutex_lock(&suspending_task_mtx);
> +	result = (suspending_task == current);
> +	mutex_unlock(&suspending_task_mtx);
> +	return result;
> +}

If suspending_task == current then you are guaranteed to be serialized, 
because everything a single task does is serial.

quoted text
> @@ -1162,7 +1162,10 @@ void device_destroy(struct class *class,
>  	dev = class_find_device(class, &devt, __match_devt);
>  	if (dev) {
>  		put_device(dev);
> -		device_unregister(dev);
> +		if (in_suspend_context())
> +			device_pm_schedule_removal(dev);
> +		else
> +			device_unregister(dev);
>  	}
>  }

But what about device_del()?  Can a similar change be made there?

Alan Stern

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