Some clients seem to rely upon the reception of BlockAckReqs to flush
their rx reorder buffer. In order to fix aggregation for these clients
carl9170 should set IEEE80211_TX_STAT_AMPDU_NO_BACK to generate a
BlockAckReq if the transmission of an AMPDU subframe fails.

This fixes aggregation problems with Intel 5100 Windows STAs (and maybe
others as well).
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The return value of the tx operation is commonly
misused by drivers, leading to errors. All drivers
will drop frames if they fail to TX the frame, and
they must also properly manage the queues (if they
didn't, mac80211 would already warn).

Removing the ability for drivers to return a BUSY
value also allows significant cleanups of the TX
TX handling code in mac80211.

Note that this also fixes a bug in ath9k_htc, the
old "return -1" there was wrong.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Tested-by: Sedat Dilek <sedat.dilek@googlemail.com> [ath5k]
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com> [rt2x00]
Acked-by: Larry Finger <Larry.Finger@lwfinger.net> [b43, rtl8187, rtlwifi]
Acked-by: Luciano Coelho <coelho@ti.com> [wl12xx]
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

"mac80211 will properly assign sequence numbers to QoS-data
frames but cannot do so correctly for non-QoS-data and
management frames because beacons need them from that counter
as well and mac80211 cannot guarantee proper sequencing."
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

commit: "carl9170: revamp carl9170_tx_prepare"
introduced a peculiar bug that would only show
up if the the module parameter noht is set to 1.

Then all outbound voice, video and background
frames would each invoke a (bogus) RTS/CTS
handshake.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The commit: "carl9170: tx path review" introduced a regression.

gcc (with -Winit-self):
tx.c:1264: warning: ‘super’ is used uninitialized in this function
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This patch fixes a few shortcomings in the tx path.

 * move temp. ampdu_[ack]_len out of txinfo->pad.

 * fix WARN_ON from tx.c:line 300 when tx_ampdu_queue
   fails to queue the frame.

 * In tx_prepare, we already have a local pointer
   to the station's ieee80211_sta struct.

 * remove a second !sta check, tx_prepare already takes
   care of that.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This patch fixes a possible lengthy stall if the device
is operating as an experimental 11n AP and an STA
[during heavy txrx action] suddenly signalized to go
off-channel (old NetworkManager), or (sleep - which is
unlikely, because then it wouldn't be *active* at all!?).

Because the driver has to manage the BA Window, the
sudden PSM transition can leave active uplink BA
sessions to the STA in a bad state and a proper
cleanup is needed.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

David Miller complained about the driver's excessive use
of variables in __packed structs. While I did not fully
agree with his sole "performance" argument on all accounts.
I do see some room for improvement in hot-paths on
architectures without an efficient access to unaligned
elements.

This first patch (dare I say?) optimizes an important tx
hot-path in the driver: carl9170_tx_prepare.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This patch removes some cruft, which survived
the RFC review phase.

Originally, carl9170_tx_ampdu_queue erroneously
dropped a lot of frames. As a result the ampdu
scheduler bogged down quite frequently and the
affected BA session timed out.

However this bug has been fixed and the WA and
its debugfs counter is no longer useful.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>