Alan Stern <st...@rowland.harvard.edu> writes: > On Tue, 13 May 2014, Rafael J. Wysocki wrote: > >> > A wakeup request from the hardware could cause a runtime resume to >> > occur at this time. The barrier wouldn't prevent that. >> > >> > It's unlikely, I agree, but not impossible. >> >> Yeah, I didn't think about that. > > Come to think of it, if the hardware sends a wakeup request then it > must have been enabled for remote wakeup. And if the hardware settings > are appropriate for system suspend then it must be enabled for system > wakeup. Consequently a wakeup from the hardware ought to abort the > system suspend in any case. So maybe we don't care about this > scenario. > > On the other hand, there may be other mechanisms that could cause a > runtime resume at this inconvenient time. A timer routine, for > instance.
Another common case is when device X depends on device Y in it's ->prepare or ->suspend path (e.g. need to write to an I2C connected GPIO/PMIC) in which case, device Y (and the I2C bus) would be runtime resumed during device X's ->prepare or ->suspend path, and possibly after device Y (or the I2C busses) ->prepare and ->suspend. Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
