Re: suggestion on resumption

[Oliver Neukum <oliver@neukum.org>]

Am Freitag, 27. November 2009 18:43:12 schrieb Alan Stern:
> > But the resume method in the driver doesn't learn. It is an extrem hassle
> > not to know whether you are called synchronously (ie from open which
> > already holds a lock) or asynchronously (which means you need to guard
> > against open)
> 
> With the new Runtime PM framework, there isn't always a one-to-one 
> correspondence between resume requests and method callbacks.  So the 
> "reason" for a callback isn't always well defined.  And even if it 
> were, the callback might happen in a different thread from the request.

That is exactly what I need to know.

> The way to guard against open from an asynchronous context is to 
> approach the problem the other way around: Guard against async contexts 
> while open is running.  In other words, have open do an autoresume.

That is the problem locking requirements are different when I do that
and I don't know what's the case.

	Regards
		Oliver