Am Mittwoch, 7. Oktober 2009 19:23:59 schrieb Alan Stern: > > We can take the port->mutex lock in the throttle/unthrottle methods as > > far as I can see - there are no obvious problem cases. We do call > > ->throttle and ->unthrottle from the ldisc open but this occurs outside > > of any call to the tty driver open/close method so I don't see any > > deadlock. > > > > It adds an ordering of termios lock before port mutex when taking both > > but that's not a problem and really implicit in the structure of the code > > anyway. > > Does this imply that unthrottle should try to autoresume? There does > appear to be a potential race between unthrottle and autosuspend. The race exists. But I don't think unthrottle should autoresume. It would be better to just set a flag and defer this to resume. If the device supports remote wakeup there'll be no need to autoresume, if not, throttle/unthrottle are too rare to justify the complexity. Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
