Re: [PATCH] USB: separate autosuspend from external suspend

On Wed, 14 Mar 2007, Oliver Neukum wrote:

> Am Dienstag, 13. März 2007 21:37 schrieb Alan Stern:
> > +/**
> > + * usb_external_resume_device - external resume of a USB device and its interfaces
> > + * @udev: the usb_device to resume
> > + *
> > + * This routine handles external resume requests: ones not generated
> > + * internally by a USB driver (autoresume) but rather coming from the user
> > + * (via sysfs), the PM core (system resume), or the device itself (remote
> > + * wakeup).  @udev's usage counter is unaffected.
> > + *
> > + * The caller must hold @udev's device lock.
> > + */
> > +int usb_external_resume_device(struct usb_device *udev)
> >  {
> 
> > +	usb_pm_lock(udev);
> > +	udev->auto_pm = 0;
> > +	status = usb_resume_both(udev);
> > +	usb_pm_unlock(udev);
> > +
> > +	/* Now that the device is awake, we can start trying to autosuspend
> > +	 * it again. */
> > +	if (status == 0)
> > +		usb_try_autosuspend_device(udev);
> >  	return status;
> 
> Is itr sensible to resume a device which autosuspend had suspended?

Sure.  For example, let's say the user writes "-1" to the 
power/autosuspend file.  The kernel sets the delay to -1 (thereby 
disabling autosuspend in the future) and wakes up the device.

Or maybe the device sends a remote wakeup request, so the kernel has to 
resume it.

Alan Stern


-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
[email protected]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel