On Wed, 2009-02-25 at 20:39 +0800, Helmut Schaa wrote: > Argh! Just found out why dev_activate is called such late after > netif_carrier_on: > > ipw2100 calls netif_carrier_on followed by netif_wake_queue when the > driver > moves from associating to associated state. netif_carrier_on will then > call linkwatch_fire_event. However the carrier_on event is not treated > as > urgent and as such the event is delayed (and thus dev_activate too). > > An event is considered urgent if the netdev is running, has a carrier > _and_ any of the TX qdiscs changed. Since ipw2100 first calls > carrier_on, > the last condition is not met and thus the event is not considered > urgent and gets delayed. Calling netif_wake_queue() before netif_carrier_on() is not correct in semantics. Even it works, it looks like a workaround hack. I still think making a sync version of netif_carrier_on is the way to go. > Just changing the order to first wake up the queues followed by the > carrier_on results in an urgent event. I ran a few tests with that > change > (+ frame buffering patch) and wasn't able to trigger the race again. > > I'll fold that into the frame buffer patch and send it to > ipw2100-devel > once I finished the tests. Sounds good. Thanks, -yi -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
