On Wed, Jan 22, 2014 at 02:33:14PM +0100, Helmut Schaa wrote:
> On Wed, Jan 22, 2014 at 2:09 PM, Karl Beldan <karl.beldan@xxxxxxxxx> wrote:
> > On Wed, Jan 22, 2014 at 01:34:39PM +0100, Johannes Berg wrote:
> >> Hmm. I guess you're right about the spec, but I vaguely remember races
> >> in this with the delBA going out too soon or so?
> >>
> >
> > Indeed, this was intended by cf6bb79 ("Use appropriate TID for sending
> > BAR, ADDBA and DELBA frames") and I overlooked it .. will look into it,
> > thanks.
> > I Cced Helmut who authored the said commit.
>
> You're right. There were some issues with that, but that was 2 years ago :)
>
> Sending ADDBA over AV_VO should be safe.
> If a DELBA is sent as AC_VO it might get received before the last AMPDU
> of the BlockAck session. So, the pending AMPDUs will get dropped at the
> receiver.
>
> In theory this could also be avoided by properly flushing all pending AMPDUs
> of the TID in question from the hw queues or by waiting for the tx status
> of all pending AMPDUs.
>
I just looked at the code with your change in mind and couldn't find any
issue caused by sending {add,del}ba on AC_VO.
As of today, a delba is sent only after a driver has called 'purposely'
ieee80211_stop_tx_ba_cb_irqsafe so I see no issue with the delba either,
do you see one today ?
Johannes, does it look good to you ? maybe add some comments in the
changelog relating to cf6bb79 ?
Karl
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