Bug 165021

Description Adrian Chadd 2012-02-12 03:00:25 UTC

If wlan_tkip/wlan_ccmp aren't loaded but are required by the hostap, the station mode code will:

* attempt to associate
* succeed
* mark wlanX as UP
* note that the required encryption type is not active
* mark wlanX as DOWN

. then 5 seconds later, "ath0: device timeout" shows up.

Fix: 

After enabling debugging, I discovered this sequence of events:

* a frame was being queued to the hardware - in this instance, a DISCONNECT frame;
* the state would then transition to DOWN;
* the IER was disabled - ie, HAL_INT_GLOBAL was cleared and something called ath_hal_intrset(); so the interrupt wouldn't occur;
* the watchdog timer would kick in and call ath_reset();
* there'd be at least one completed frame in the TX queue, status OK - so it did go out.

The actual cause seems to be that the state transition is going from RUN -> INIT, and this is causing interrupts to be disabled.

ath_newstate() is causing a state transition to INIT, which disables interrupts and blocks the ath taskqueue. Trouble is, this doesn't stop/flush any of the currently pending hardware TX and this is what's eventually causing the watchdog timeout - although the hardware has completed the TX, the driver has disabled all methods of actually being notified about it.
How-To-Repeat: * compile ath/net80211 as modules
* load wlan and ath/ath_pci - but don't load wlan_wep/wlan_tkip/wlan_ccmp
* attempt to associate to a network which requires encryption