Re: Information in PM messages

[David Brownell <david-b@pacbell.net>]

On Friday 09 June 2006 7:24 am, Alan Stern wrote:
> On Thu, 8 Jun 2006, David Brownell wrote:
> 
> > > 	A message whose source is USER or DRIVER should not be
> > > 	allowed to resume a device that was suspended by a message
> > > 	whose source was SYSTEM.  In other words, runtime PM and
> > > 	autoresume should not interfere with a system sleep transition.
> > 
> > Why wouldn't that be entirely the driver's responsibility, and
> > something they don't need API changes to achieve?
> 
> Perhaps we don't need to worry about this.
> 
> After all, in most cases it's impossible for a device which is suspended
> as part of a system-sleep transition to get either a runtime-PM resume or
> an autoresume request.  It can only happen in situations where the
> system-sleep did not first freeze all tasks.  In those situations people
> may agree that it is acceptable for the sleep transition to be aborted by
> a user request or an autoresume.
> 
> If that is so then yes, we don't need to alter the PM message structures
> in this way.

I think that's pretty much what I was saying by insisting that the driver's
PM state transitions have to be correct... invalid transtions will always
be invalid, regardless of whether or not the API gets complexified!  :)

- Dave