misc/165021: [ath] ath device timeout during scan/attach,
if wlan_ccmp/wlan_tkip isn't loaded
adrian at FreeBSD.org
Sun Feb 12 03:00:26 UTC 2012
>Synopsis: [ath] ath device timeout during scan/attach, if wlan_ccmp/wlan_tkip isn't loaded
>Arrival-Date: Sun Feb 12 03:00:25 UTC 2012
>Originator: Adrian Chadd
9.0-RELEASE i386, but with -HEAD net80211/ath driver.
If wlan_tkip/wlan_ccmp aren't loaded but are required by the hostap, the station mode code will:
* attempt to associate
* 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.
* 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
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.
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