With "mac80211/minstrel_ht: add support for using CCK rates"
minstrel_ht selects legacy CCK rates as viable rates for
outgoing frames which might be sent as part of an A-MPDU
[IEEE80211_TX_CTL_AMPDU is set].

This behavior triggered the following WARN_ON in the driver:
> WARNING: at carl9170/tx.c:995 carl9170_op_tx+0x1dd/0x6fd
The driver assumed that the rate control algorithm made a
mistake and dropped the frame.

This patch removes the noisy warning altogether and allows
said A-MPDU frames with CCK sample and/or fallback rates to
be transmitted seamlessly.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This patch moves parts of carl9170_update_beacon
into separate subroutines, so the parts become
more manageable.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Dan Carpenter reported that smatch detected a potential
problem with the code [1]:
 drivers/net/wireless/ath/carl9170/tx.c:1488 carl9170_op_tx()
  error: we previously assumed 'sta' could be null (see line 1482)

 drivers/net/wireless/ath/carl9170/tx.c
  1482  if (sta) {
           ^^^^^ New check.
  [...]
  1485  }
  1487  if (info->flags & IEEE80211_TX_CTL_AMPDU) {
  1488    run = carl9170_tx_ampdu_queue(ar, sta, skb);
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   Old dereference of "sta" inside the call to carl9170_tx_ampdu_queue().

A range of solutions have been discussed in [2] and
we agreed on the following: "
> we might as well add a comment to carl9170_tx_ampdu_queue
> and explain the situation [in a way that's obvious to a
> human reader]. This way we can save the "if"... which is
> a small win since carl9170_op_tx is sort of a hot-path.
Putting a comment there is fine. Without the comment
it's easy for a human reader to get confused why the
check is there. So long as humans can read the code,
that's all that matters."

[1] <http://www.spinics.net/lists/linux-wireless/msg94526.html>
[2] <http://www.spinics.net/lists/linux-kernel-janitors/msg14953.html>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Remove the control.sta pointer from ieee80211_tx_info to free up
sufficient space in the TX skb control buffer for the upcoming
Transmit Power Control (TPC).
Instead, the pointer is now on the stack in a new control struct
that is passed as a function parameter to the drivers' tx method.
Signed-off-by: NThomas Huehn <thomas@net.t-labs.tu-berlin.de>
Signed-off-by: NAlina Friedrichsen <x-alina@gmx.net>
Signed-off-by: NFelix Fietkau <nbd@openwrt.org>
[reworded commit message]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This patch adds an alternative tx status path
for BlockAck Requests as the hardware doesn't
recognize that a BlockAck Requests is usually
acked with a BlockAck and not a legacy ACK.

Without this patch, the stack would constantly
resent old and stale BARs. So, depending on the
receiver stack, this could lead to:

 - "stuck" ba sessions and package loss, as the
   stale BAR would reset the sequence each time.

 - lots of reorder releases.

 - ...
Reported-by: NSean Patrick Santos <quantheory@gmail.com>
Reported-by: NMikołaj Kuligowski <mikolaj.q@wp.pl>
Reported-by: NPer-Erik Westerberg <per-erik.westerberg@bredband.net>
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

IEEE80211_TX_MAX_RATES can be reduced from 5 to 4 as there
is no current hardware supporting a rate chain with 5 multi
rate stages (mrr), so 4 mrr stages are sufficient.

The memory that is freed within the ieee80211_tx_info struct
will be used in the upcoming Transmission Power Control (TPC)
implementation.
Suggested-by: NFelix Fietkau <nbd@openwrt.org>
Signed-off-by: NThomas Huehn <thomas@net.t-labs.tu-berlin.de>
[reword commit message]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

That commit intended for 3.4 renamed IEEE80211_TX_CTL_POLL_RESPONSE as
IEEE80211_TX_CTL_NO_PS_BUFFER.  Meanwhile, "carl9170: fix frame delivery
if sta is in powersave mode" added a reference to
IEEE80211_TX_CTL_POLL_RESPONSE in the fixes stream for 3.3.  This simple
patch fixes that merge boo-boo.
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Nicolas Cavallari discovered that carl9170 has some
serious problems delivering data to sleeping stations.

It turns out that the driver was not honoring two
important flags (IEEE80211_TX_CTL_POLL_RESPONSE and
IEEE80211_TX_CTL_CLEAR_PS_FILT) which are set on
frames that should be sent although the receiving
station is still in powersave mode.

Cc: stable <stable@vger.kernel.org>
Reported-by: NNicolas Cavallari <Nicolas.Cavallari@lri.fr>
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

On Access Point mode, when transmitting a packet, if the destination
station is in powersave mode, we abort transmitting the packet to the
device queue, but we do not reclaim the allocated memory.  Given enough
packets, we can go in a state where there is no packet on the device
queue, but we think the device has no memory left, so no packet gets
transmitted, connections breaks and the AP stops working.

This undo the allocation done in the TX path when the station is in
power-save mode.
Signed-off-by: NNicolas Cavallari <cavallar@lri.fr>
Acked-by: NChristian Lamparter <chunkeey@googlemail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This patch implements a simple way of reducing the
output power of the device by a configurable upper
limit.
Requested-by: NHarshal Chhaya <harshal@gmail.com>
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

In the past, it was fine to simply call
dev_kfree_skb when it was impossible to
transmit a skb. However, with the new
tx status API:
"mac80211: implement wifi TX status"
Every loose skb needs to be handed back
to mac80211.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Previously the driver did not care if TX_CTL_REQ_TX_STATUS
was set on aggregated frames or not and it would silently
drop successfully sent frames if possible [much like:
"no news is good news!"].

But, TX_CTL_REQ_TX_STATUS was invented for a reason and
no tx status report should ever be dropped if it is set.
Reported-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Harshal Chhaya discovered during network tests, that
several of his clients dropped-off the network. The
captured packets shows that the beacons sent by the
AP are at a much lower power than the other data
packets.

The reason for this mishap: The driver never updated
the beacon phy register, so all beacons were always
sent at the lowest power.

Reference: http://marc.info/?l=linux-wireless&m=131067225105801Reported-by: NHarshal Chhaya <harshal@gmail.com>
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>

tx.c: In function ‘carl9170_tx_accounting_free’:
tx.c:159:28: warning: variable ‘txinfo’ set but not used
tx.c: In function ‘carl9170_tx_status_process_ampdu’:
tx.c:383:27: warning: variable ‘ar_info’ set but not used
tx.c: In function ‘__carl9170_tx_process_status’:
tx.c:626:27: warning: variable ‘arinfo’ set but not used
tx.c: In function ‘carl9170_tx_ampdu_queue’:
tx.c:1324:15: warning: variable ‘max’ set but not used
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Using the ieee80211_sta_block allows the PS code
to handle awake->doze->awake transitions of our
clients in a race-free manner.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

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>