On Wed, Aug 14, 2019 at 1:40 AM Tony Lindgren <t...@atomide.com> wrote: > > * Stephen Boyd <swb...@chromium.org> [691231 23:00]: > > I also notice that device_set_wakeup_capable() has a check to see if the > > device is registered yet and it skips creating sysfs entries for the > > device if it isn't created in sysfs yet. Why? Just so it can be called > > before the device is created? I guess the same logic is handled by > > dpm_sysfs_add() if the device is registered after calling > > device_set_wakeup_*(). > > Hmm just guessing.. It's maybe because drivers can enable and disable > the wakeup capability at any point for example like driver/net drivers > do based on WOL etc? > > > There's two approaches I see: > > > > 1) Do a similar check for device_set_wakeup_enable() and skip > > adding the wakeup class until dpm_sysfs_add(). > > > > 2) Find each case where this happens and only call wakeup APIs > > on the device after the device is added. > > > > I guess it's better to let devices have wakeup modified on them before > > they're registered with the device core? > > I think we should at least initially handle case #1 above as multiple > places otherwise seem to break. Then maybe we could add a warning to > help fix all the #2 cases if needed?
Makes sense. For case#1, we could also just register the wakeup source without specifying the parent device if the latter hasn't been registered yet. Userspace won't be able to associate a wakeup source to the parent device. But I think it's a reasonable fix, assuming we want to fix devices not being added before calling wakeup APIs #2.
