On Thu, May 14, 2015 at 11:51:10AM -0400, Alan Stern wrote:
> On Wed, 13 May 2015, Felipe Balbi wrote:
>
> > This brings up a question, actually. What to do with devices which were
> > already runtime suspended when user initiated suspend-to-ram ? Do we
> > leave wakeups enabled, or do we revisit device_may_wakeup() and
> > conditionally runtime_resume the device, disable wakeup, and let its
> > ->suspend() callback be called ?
>
> In theory, the subsystem/device drivers already have code do this.
> They're supposed to, anyway. The USB host stack does it in
> drivers/usb/core/driver.c:choose_wakeup().
that answers the question, specifically, this comment and piece of code
do:
1395 static void choose_wakeup(struct usb_device *udev, pm_message_t msg)
1396 {
[...]
1409 /* Enable remote wakeup if it is allowed, even if no interface drivers
1410 * actually want it.
1411 */
1412 w = device_may_wakeup(&udev->dev);
1413
1414 /* If the device is autosuspended with the wrong wakeup setting,
1415 * autoresume now so the setting can be changed.
1416 */
1417 if (udev->state == USB_STATE_SUSPENDED && w != udev->do_remote_wakeup)
1418 pm_runtime_resume(&udev->dev);
1419 udev->do_remote_wakeup = w;
1420 }
so that's something that also needs to be taken into consideration.
Thanks
--
balbi
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