Re: [linux-pm] wacom + runtime PM = AA deadlock

[Oliver Neukum <oneukum@suse.de>]

Am Dienstag, 14. September 2010, 16:01:14 schrieb Alan Stern:
> On Tue, 14 Sep 2010, Oliver Neukum wrote:
> 
> > Am Montag, 13. September 2010, 22:02:16 schrieb Alan Stern:
> > > > > Is there any point in resuming the device during close() just in order
> > > > > to kill the interrupt URB?  It seems counterproductive -- if the device 
> > > > > had been suspended then there wouldn't be any interrupt URB to kill in 
> > > > > the first place.
> > > > 
> > > > Suppose the device does not support remote wakeup. It would never
> > > > be autosuspended while it is open, but simply resetting the flag
> > > > would never reach the PM layer.
> > > 
> > > Whoops, that's right.  I didn't see the assignment to 
> > > needs_remote_wakeup.
> > 
> > Should I have used usb_autopm_get_interface_no_resume()?
> 
> That actually would work.  It's a good idea.  The only drawback (not a
> big one) is that if the device _was_ suspended with remote wakeup
> enabled, doing this wouldn't turn off remote wakeup.  I think that
> doesn't matter.

I am afraid it does matter as devices whose remote wakeup is enabled
may draw more power.

	Regards
		Oliver