Re: [linux-pm] Fundamental flaw in system suspend, exposed by freezer removal

[Alan Stern <stern@rowland.harvard.edu>]

On Mon, 3 Mar 2008, Rafael J. Wysocki wrote:

> > > Perhaps it's better to include dpm_sysfs_add() into device_pm_add(), since we
> > > are going the make the return a result anyway?
> > 
> > Yes.
> 
> Okay, I'll prepare a patch for that, on top of the one introducing the
> 'sleeping' field into 'struct dev_pm_info' (posting in a while).

While you're at it, could you add a field to indicate whether 
begin_sleep() has been called?  It would help prevent multiple calls to 
that method when a race does occur, and it could be useful for drivers 
as well.

> The question remains what we're going to do with the drivers without pm_ops
> pointers in the long run (in the short run we will use the legacy callbacks in
> that cases, if defined).

One possibility is to unbind those drivers at the start of a sleep
transition and reprobe them at the end.  Another possibility is to
ignore the lack of PM support and hope it doesn't cause any problems.

Alan Stern