Re: [RFC] PCI: Runtime power management

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Saturday 15 August 2009, Matthew Garrett wrote:
> On Sat, Aug 15, 2009 at 10:54:23PM +0200, Rafael J. Wysocki wrote:
> 
> > runtime_wakeup - if set, the device is allowed to do remote wakeup at run time
> >   That could be represented as 'runtime_wakeup' under 'power' with the
> >   following values:
> >   * no value (empty file) is 'runtime' is 'disabled'
> >   * 'enabled'
> >   * 'disabled'
> >   To set/unset the user space writes 'enabled'/'disabled' to it, respectively.
> >   The default is set.
> 
> Why would you ever want runtime_wakeup to be false unless 
> runtime_forbidden is true? Surely the point of runtime power management 
> is to be transparent to the user, in which case remote wakeup is 
> required?

Well, this was exactly my point previously. :-)

Still, although for the majority of devices 'runtime_wakeup' disabled would
mean no runtime PM at all IMO, there may be devices that actually work without
remote wakeup, although they support it in general.

I can even imagine a scenario where this setting might be useful, like when
we don't want a network adapter to be woken up from the outside.

Thanks,
Rafael