Re: [PATCH] mac80211: fix rate_control_send_low warnings for delbas

[Vasanthakumar Thiagarajan <vasanth@atheros.com>]

On Wed, Sep 29, 2010 at 05:28:35AM +0530, Luis R. Rodriguez wrote:
> On Tue, Sep 28, 2010 at 4:02 PM, Jouni Malinen <j@w1.fi> wrote:
> > On Tue, Sep 28, 2010 at 03:29:45PM -0700, Luis R. Rodriguez wrote:
> >
> >> Added support for cfg80211/mac80211 to cleanly roam between two BSSes
> >> on an ESS by allowing the station to reassociate to an old AP and
> >> only when that is done drop the old association. What we forgot to
> >> take into consideration is that when we disassociate with the older
> >> AP we may need to transmit frames to that AP and those frames may
> >> actually be intended to go under a different channel and even sometimes
> >> a completely separate band than the new APs.
> >
> > which frames are you talking about here?
> 
> ieee80211_send_delba()
> 
> > When reassociating to a new BSS
> > in an ESS, there should be no need to transmit frames to the old AP
> > anymore, i.e., we are never associated with more than one BSS (when
> > talking about a single vif). We could just drop any potential TX frame
> > to the old AP after the moment the new AP is marked associated.
> 
> That's the goal of this patch.

>From my debugging, this happens when cleaning up BA session for old
AP but on a different channel (where we just authenticated with
another AP) just before starting association with the new AP.
Though local->work_work takes care of moving to right channel,
it is possible that cfg80211 receives NL80211_CMD_ASSOCIATE before
local->work_work configures the hw back to old AP's channel (that
is what happening in our case).


Vasanth