Commit Graph

1659 Commits

Author SHA1 Message Date
Pedro F. Giffuni
f6b6084b8e dev/ath: minor spelling fixes in comments.
No functional change.

Reviewed by:	adrian
2016-05-02 19:56:48 +00:00
Adrian Chadd
a039118792 [ath] initialise do_ldpc to 0.
I .. can't believe I missed this.

This showed up because the AP was TX'ing LDPC to an iwm(4) chipset,
which didn't advertise LDPC and doesn't /accept/ LDPC.  Amusingly, all
the two other FreeBSD 11n parts I had tested with (AR9380, Intel 7260)
and I completely forgot to test on ye olde hardware.

That'll teach me.

Tested:

* AR9580 (AP) - Intel 7260 (STA), AR9380 (STA), Intel 6205 (STA)
2016-04-29 18:53:16 +00:00
Adrian Chadd
ce725c8e00 [ath] Add LDPC transmit support.
LDPC adds better transmit reliability if both ends support it.

You in theory can do both STBC and LDPC at the same time.
If I see issues I'll disable it.

* Only enable it if both ends of a connection negotiate it.
* Disable it if any rate is non-11n.
* Count both LDPC TX and STBC TX.

Tested:

* AR9380, STA mode
2016-04-29 01:53:45 +00:00
Adrian Chadd
82525db1eb [ath] turn the BA hardware bug back into a printf().
I saw this happen a couple of times and all I saw was a dump of the
transmit descriptors.  Log the message for now so I can see whta happened.
2016-04-29 01:52:06 +00:00
Adrian Chadd
3c6b488b01 [ath] Add counters for STBC TX and LDPC TX.
This is a big no-op until the TX path changes to enable LDPC TX are
added.
2016-04-29 01:51:27 +00:00
Adrian Chadd
9f3a915030 [ath] add LDPC capability support and LDPC RX support.
This enables LDPC receive support for the AR9300 chips that support it.
It'll announce LDPC support via net80211.

Tested:

* AR9380, STA mode
* AR9331, (to verify the HAL didn't attach it to a chip which
  doesn't support LDPC.)

TODO:

* Add in net80211 machinery to make this configurable at runtime.
2016-04-26 01:37:03 +00:00
Adrian Chadd
f026d6931a [ath] obey the STBC flag setting in iv_flags_ht
Add support for the FHT_STBC_TX flag in iv_flags_ht, so it'll now obey
the per-vap ifconfig stbctx flag.

This means that we can do STBC TX on one vap and not another VAP.
(As well as STBC RX on said vap; that changes the HTCAP announcement.)
2016-04-26 01:34:21 +00:00
Andriy Voskoboinyk
31021a2b4e net80211: replace internal LE_READ_*/LE_WRITE_* macro with system
le*dec / le*enc functions.

Replace net80211 specific macros with system-wide bytestream
encoding/decoding functions:
- LE_READ_2 ->  le16dec
- LE_READ_4 ->  le32dec
- LE_WRITE_2 -> le16enc
- LE_WRITE_4 -> le32enc

+ drop ieee80211_input.h include, where it was included for these
operations only.

Reviewed by:	adrian
Differential Revision:	https://reviews.freebsd.org/D6030
2016-04-20 18:29:30 +00:00
Pedro F. Giffuni
74b8d63dcc Cleanup unnecessary semicolons from the kernel.
Found with devel/coccinelle.
2016-04-10 23:07:00 +00:00
Adrian Chadd
afa4433355 [ath] Only process beacon frames for the IBSS/BSSID if appropriate.
* Don't use arbitrary frames for the average RX RSSI - only frames
  from the current BSSID

* Don't log / do the syncbeacon logic for another BSSID and definitely
  don't do the syncbeacon call if we miss beacons outside of STA mode.

* Don't do the IBSS merge bits if the current node plainly won't ever
  match our current BSS (ie, the IBSS doesn't have to match, but all
  the same bits that we check in ieee80211_ibss_merge() have to match.)

Tested:

* ath(4), AR9380, IBSS mode, surrounded by a lot of IBSS 11ac networks.

Sponsored by:	Eva Automation, Inc.
2016-04-09 00:58:38 +00:00
Adrian Chadd
b8e29e065d [net80211] migrate the time_* macros to ieee80211_* namespace.
It turns out that these will clash very annoyingly with the linux
macros in the linuxkpi layer, so let the wookie^Wlinux win.

The only user that I can find is ath(4), so fix it there too.
2016-03-30 00:44:10 +00:00
John Baldwin
cbc4d2db75 Remove taskqueue_enqueue_fast().
taskqueue_enqueue() was changed to support both fast and non-fast
taskqueues 10 years ago in r154167.  It has been a compat shim ever
since.  It's time for the compat shim to go.

Submitted by:	Howard Su <howard0su@gmail.com>
Reviewed by:	sephe
Differential Revision:	https://reviews.freebsd.org/D5131
2016-03-01 17:47:32 +00:00
Adrian Chadd
b258556759 Fix up the ath(4) device names for QCA chipsets.
Submitted by:	Tobias Kortkamp <t@tobik.me>
2016-02-29 02:40:58 +00:00
Adrian Chadd
17f42e0d6b [ath] remove the inline version of the register access macros.
These are going to be much more efficient on low end embedded systems
but unfortunately they make it .. less convenient to implement correct
bus barriers and debugging.  They also didn't implement the register
serialisation workaround required for Owl (AR5416.)

So, just remove them for now.  Later on I'll just inline the routines
from ah_osdep.c.
2016-01-03 17:58:11 +00:00
Adrian Chadd
fdee6e3bba ... and that would've never worked. Sorry!
(Note: everything I tested on locally has ATH_DEBUG / AH_DEBUG set.)
2016-01-02 18:32:20 +00:00
Adrian Chadd
ef91dbcec6 [ath] add explicit bus barriers.
The ath hal and driver code all assume the world is an x86 or the
bus layer does an explicit bus flush after each operation (eg netbsd.)

However, we don't do that.

So, to be "correct" on platforms like sparc64, mips and ppc (and maybe
ARM, I am not sure), just do explicit barriers after each operation.

Now, this does slow things down a tad on embedded platforms but I'd
rather things be "correct" versus "fast."  At some later point if someone
wishes it to be fast then we should add the barrier calls to the HAL and
driver.

Tested:

* carambola 2 (AR9331.)
2016-01-02 17:14:22 +00:00
Adrian Chadd
ff066b54ec fix ht/40 configuration for ar9331 (hornet).
The synth programming here requires the real centre frequency,
which for HT20 channels is the normal channel, but HT40 is
/not/ the primary channel.  Everything else was using 'freq',
which is the correct centre frequency, but the hornet config
was using 'ichan' to do the lookup which was also the primary
channel.

So, modify the HAL call that does the mapping to take a frequency
in MHz and return the channel number.

Tested:

* Carambola 2, AR9331, tested both HT/20 and HT/40 operation.
2015-11-30 06:26:59 +00:00
Adrian Chadd
2c9b30a91f [ath_hal] use the correct revision information for QCA953x.
This probe/attaches correctly in my local branch and now displays
a useful message:

ath0: <Qualcomm Atheros QCA953x> at mem 0x18100000-0x1811ffff irq 0 on nexus0
...
ath0: AR9530 mac 1280.0 RF5110 phy 0.0
2015-11-28 06:50:09 +00:00
Adrian Chadd
70aca315ac * Add device string for QCA955x (scorpion);
* Add device ID and device string for QCA953x (honeybee).
2015-11-28 00:27:16 +00:00
Adrian Chadd
19b34b5685 wrap in ATH_DEBUG.
Thanks sparc64 build!
2015-11-28 00:14:37 +00:00
Adrian Chadd
20b0b9ea74 [ath] conditionally print out the rate series information if ATH_DEBUG_XMIT is set. 2015-11-27 22:33:40 +00:00
Adrian Chadd
94a88508a5 [ath] listen to all beacons in IBSS and software beacon miss.
I added MYBEACON support a while ago to listen to beacons that are only
for your configured BSSID.  For AR9380 and later NICs this results in
a lot less chip wakeups in station mode as it then only shows you beacons
that are destined to you.

However in IBSS mode you really do want to hear all beacons so you can do
IBSS merges.  Oops.

So only use MYBEACON for STA + not-scanning, and just use BEACON for
the other modes it used to use BEACON for.

This doesn't completely fix IBSS merges though - there are still some
conditions to chase down and fix.
2015-11-25 18:24:49 +00:00
Adrian Chadd
b45de1ebcd [ath] migrate ioctl and busdma memory operations out into separate source files.
This should be a big no-op pass; and reduces the size of if_ath.c.

I'm hopefully soon going to take a whack at the USB support for ath(4)
and this'll require some reuse of the busdma memory code.
2015-11-24 03:42:58 +00:00
Renato Botelho
1ce017241b Fix kernel build, broken in r290612
Approved by:	adrian
2015-11-09 20:22:59 +00:00
Adrian Chadd
f50e4ebf6a ath(4): begin fleshing out a "reset type" extension to force cold/warn resets.
Right now the only way to force a cold reset is:

* The HAL itself detects it's needed, or
* The sysctl, setting all resets to be cold.

Trouble is, cold resets take quite a bit longer than warm resets.

However, there are situations where a cold reset would be nice.
Specifically, after a stuck beacon, BB/MAC hang, stuck calibration results,
etc.

The vendor HAL has a separate method to set the reset reason (which is
how HAL_RESET_BBPANIC gets set) which informs the HAL during the reset path
why it occured.  This is almost but not quite the same; I may eventually
unify both approaches in the future.

This commit just extends HAL_RESET_TYPE to include both status (eg BBPANIC)
and type (eg do COLD.)  None of the HAL code uses it yet though;  that'll
come later.

It also is a big no-op in each HAL - I need to go teach each of the HALs
about cold/warm reset through this path.
2015-11-09 15:59:42 +00:00
Adrian Chadd
dccb3981eb ath(4) - reflect whether this is a full or fast channel change.
It's no longer "outdoor."
2015-11-07 00:51:51 +00:00
Adrian Chadd
da4552abb0 ath(4) - don't try to free buffers / return an error if we've committed
to transmit the buffer.

ath_tx_start() may manipulate/reallocate the mbuf as part of the DMA
code, so we can't expect the mbuf can be returned back to the caller.
Now, the net80211 ifnet work changed the semantics slightly so
if an error is returned here, the mbuf/reference is freed by the
caller (here, it's net80211.)

So, once we reach ath_tx_start(), we never return failure.  If we fail
then we still return OK and we free the mbuf/noderef ourselves, and
we increment OERRORS.
2015-11-03 21:11:30 +00:00
Adrian Chadd
d957a93abe net80211: move ieee80211_free_node() call on error from ic_raw_xmit() to ieee80211_raw_output().
This doesn't free the mbuf upon error; the driver ic_raw_xmit method is still
doing that.

Submitted by:	<s3erios@gmail.com>
Differential Revision:	https://reviews.freebsd.org/D3774
2015-10-12 04:55:20 +00:00
Adrian Chadd
d07be335a0 net80211: separate mbuf cleanup from ieee80211_fragment()
* Create ieee80211_free_mbuf() which frees a list of mbufs.
* Use it in the fragment transmit path and ath / uath transmit paths.
* Call it in xmit_pkt() if the transmission fails; otherwise fragments
  may be leaked.

This should be a big no-op.

Submitted by:	<s3erios@gmail.com>
Differential Revision:	https://reviews.freebsd.org/D3769
2015-10-12 03:27:08 +00:00
Adrian Chadd
dc809fc15f Flip on fast frames support for AR5416 and AR9300 series NICs.
This was off because the net80211 aggregation code was using the same
state pointers for both fast frames and ampdu tx support which led to some
pretty unfortunate panic-y behaviour.

Now that net80211 doesn't panic, let's flip this back on.

It doesn't (yet) do the horrific sounding thing of A-MPDU aggregates
of fast frames; that'll come next.  It's a pre-requisite to supporting
AMSDU + AMPDU anyway, which actually speeds things up quite considerably
(think packing lots of little ACK frames into a single AMSDU.)

Tested:

* QCA955x SoC, AP mode
* AR5416, STA mode
* AR9170, STA mode (with local fast frame patches)
2015-10-10 00:13:45 +00:00
Kevin Lo
8aabf601d1 Remove the unnecessary cast. 2015-10-05 05:24:16 +00:00
Adrian Chadd
210ab3c258 net80211: drop ieee80211_beacon_offsets parameter from ieee80211_beacon_alloc() and ieee80211_beacon_update()
Submitted by:	<s3erios@gmail.com>
Differential Revision:	https://reviews.freebsd.org/D3659
2015-10-03 22:12:25 +00:00
Adrian Chadd
bc813c40bf net80211: drop redundant 3rd parameter from iv_key_set().
The MAC can be fetched from the key struct.

I added the ndis updates to make it compile.

Submitted by:	<s3erios@gmail.com>
Differential Revision:	https://reviews.freebsd.org/D3657
2015-10-03 21:48:27 +00:00
Adrian Chadd
b94ab33751 Remove the references to the TX IC lock - i ended up solving this
using net80211 to seralise encap+xmit, so now it's a non-issue.
2015-09-29 03:37:17 +00:00
Adrian Chadd
0cf00015be net80211: include one copy of struct ieee80211_beacon_offsets into ieee80211vap
Submitted by:	Andriy Voskoboinyk <s3erios@gmail.com>
Differential Revision:	https://reviews.freebsd.org/D3658
2015-09-22 06:34:07 +00:00
Adrian Chadd
d6166def28 net80211 & wireless drivers: remove duplicate defines (noop)
* IEEE80211_DIR_DSTODS(wh) -> IEEE80211_IS_DSTODS(wh).
* N(a) -> nitems(a).
* Remove LE_READ_2(p)/LE_READ_4(p) definitions (and include ieee80211_input.h instead).
* <drvname>_TXOP_TO_US(txop) -> IEEE80211_TXOP_TO_US(txop).
* Put IEEE80211_RV(v) into ieee80211_proto.h and remove local RV(v) definitions.

Submitted by:	Andriy Voskoboinyk <s3erios@gmail.com>
Differential Revision:	https://reviews.freebsd.org/D3705
2015-09-22 02:44:59 +00:00
Gleb Smirnoff
7a79cebfba Replay r286410. Change KPI of how device drivers that provide wireless
connectivity interact with the net80211 stack.

Historical background: originally wireless devices created an interface,
just like Ethernet devices do. Name of an interface matched the name of
the driver that created. Later, wlan(4) layer was introduced, and the
wlanX interfaces become the actual interface, leaving original ones as
"a parent interface" of wlanX. Kernelwise, the KPI between net80211 layer
and a driver became a mix of methods that pass a pointer to struct ifnet
as identifier and methods that pass pointer to struct ieee80211com. From
user point of view, the parent interface just hangs on in the ifconfig
list, and user can't do anything useful with it.

Now, the struct ifnet goes away. The struct ieee80211com is the only
KPI between a device driver and net80211. Details:

- The struct ieee80211com is embedded into drivers softc.
- Packets are sent via new ic_transmit method, which is very much like
  the previous if_transmit.
- Bringing parent up/down is done via new ic_parent method, which notifies
  driver about any changes: number of wlan(4) interfaces, number of them
  in promisc or allmulti state.
- Device specific ioctls (if any) are received on new ic_ioctl method.
- Packets/errors accounting are done by the stack. In certain cases, when
  driver experiences errors and can not attribute them to any specific
  interface, driver updates ic_oerrors or ic_ierrors counters.

Details on interface configuration with new world order:
- A sequence of commands needed to bring up wireless DOESN"T change.
- /etc/rc.conf parameters DON'T change.
- List of devices that can be used to create wlan(4) interfaces is
  now provided by net.wlan.devices sysctl.

Most drivers in this change were converted by me, except of wpi(4),
that was done by Andriy Voskoboinyk. Big thanks to Kevin Lo for testing
changes to at least 8 drivers. Thanks to pluknet@, Oliver Hartmann,
Olivier Cochard, gjb@, mmoll@, op@ and lev@, who also participated in
testing.

Reviewed by:	adrian
Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2015-08-27 08:56:39 +00:00
Adrian Chadd
3797bf0896 Remove most of the references of ifp->if_softc and replace with
references to ic->ic_softc.

This is in preparation for gleb's ifnet work.

Tested:

* ath(4), STA mode
* ath(4), hostap mode
* make universe
2015-08-17 02:04:11 +00:00
Adrian Chadd
ba2c1fbc03 Revert the wifi ifnet changes until things are more baked and tested.
* 286410
* 286413
* 286416

The initial commit broke a variety of debug and features that aren't
in the GENERIC kernels but are enabled in other platforms.
2015-08-08 01:10:17 +00:00
Gleb Smirnoff
79d2c5e857 Change KPI of how device drivers that provide wireless connectivity interact
with the net80211 stack.

Historical background: originally wireless devices created an interface,
just like Ethernet devices do. Name of an interface matched the name of
the driver that created. Later, wlan(4) layer was introduced, and the
wlanX interfaces become the actual interface, leaving original ones as
"a parent interface" of wlanX. Kernelwise, the KPI between net80211 layer
and a driver became a mix of methods that pass a pointer to struct ifnet
as identifier and methods that pass pointer to struct ieee80211com. From
user point of view, the parent interface just hangs on in the ifconfig
list, and user can't do anything useful with it.

Now, the struct ifnet goes away. The struct ieee80211com is the only
KPI between a device driver and net80211. Details:

- The struct ieee80211com is embedded into drivers softc.
- Packets are sent via new ic_transmit method, which is very much like
  the previous if_transmit.
- Bringing parent up/down is done via new ic_parent method, which notifies
  driver about any changes: number of wlan(4) interfaces, number of them
  in promisc or allmulti state.
- Device specific ioctls (if any) are received on new ic_ioctl method.
- Packets/errors accounting are done by the stack. In certain cases, when
  driver experiences errors and can not attribute them to any specific
  interface, driver updates ic_oerrors or ic_ierrors counters.

Details on interface configuration with new world order:
- A sequence of commands needed to bring up wireless DOESN"T change.
- /etc/rc.conf parameters DON'T change.
- List of devices that can be used to create wlan(4) interfaces is
  now provided by net.wlan.devices sysctl.

Most drivers in this change were converted by me, except of wpi(4),
that was done by Andriy Voskoboinyk. Big thanks to Kevin Lo for testing
changes to at least 8 drivers. Thanks to Olivier Cochard, gjb@, mmoll@,
op@ and lev@, who also participated in testing. Details here:

https://wiki.freebsd.org/projects/ifnet/net80211

Still, drivers: ndis, wtap, mwl, ipw, bwn, wi, upgt, uath were not
tested. Changes to mwl, ipw, bwn, wi, upgt are trivial and chances
of problems are low. The wtap wasn't compilable even before this change.
But the ndis driver is complex, and it is likely to be broken with this
commit. Help with testing and debugging it is appreciated.

Differential Revision:	D2655, D2740
Sponsored by:	Nginx, Inc.
Sponsored by:	Netflix
2015-08-07 11:43:14 +00:00
Adrian Chadd
70c81b2077 Add a hack-around to this fatal taskqueue running whilst the NIC
is detaching.

This mostly fixes a panic - the reset path shouldn't run whilst
the NIC is being torn down.

It's not locked, so it's "mostly" ok, but most of the rest of
the driver doesn't read sc->invalid with sensible locking. Grr.

The real solution is to cleanly tear down taskqueues in the detach/suspend
phase, but ..
2015-08-05 21:22:25 +00:00
Adrian Chadd
35aae619d7 Call the WMAC DDR flush before handling an interrupt for the
Atheros AHB (internally) connected MAC.

TODO:

* verify the interrupt was for us before doing the DDR flush.
2015-07-04 03:07:28 +00:00
Adrian Chadd
52f5515397 Wake up the hardware before doing anything in sysctl.
This stops the panics that occur on MIPS platforms when doing say,
'sysctl dev.ath.0' whilst the MAC is asleep.  The MIPS platform is
rather unforgiving in getting power-save register access wrong and you
will get all kinds of odd failures if you don't have things woken
up at the right times.

Tested:

* QCA9558 (TP-Link Archer C7 v2)
* AR9331 (Carambola 2)

.. with no VAPs configured and ath0 down (thus the MAC is definitely
   asleep.)

PR:		kern/201117
2015-07-04 02:59:30 +00:00
Gleb Smirnoff
76e6fd5d6c Use device_printf() instead of if_printf(). No functional changes. 2015-05-29 14:35:16 +00:00
Gleb Smirnoff
272f6ade9b Change three methods in struct ieee80211com, namely ic_updateslot,
ic_update_mcast and ic_update_promisc, to pass pointer to the ieee80211com,
not to the ifnet.

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2015-05-25 19:53:29 +00:00
Gleb Smirnoff
59686fe935 Set ic_softc in all 802.11 drivers. Not required right now, but will be
used quite soon.

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2015-05-25 18:50:26 +00:00
Adrian Chadd
c79f192c09 Begin plumbing ieee80211_rx_stats through the receive path.
Smart NICs with firmware (eg wpi, iwn, the new atheros parts, the intel 7260
series, etc) support doing a lot of things in firmware.  This includes but
isn't limited to things like scanning, sending probe requests and receiving
probe responses.  However, net80211 doesn't know about any of this - it still
drives the whole scan/probe infrastructure itself.

In order to move towards suppoting smart NICs, the receive path needs to
know about the channel/details for each received packet.  In at least
the iwn and 7260 firmware (and I believe wpi, but I haven't tried it yet)
it will do the scanning, power-save and off-channel buffering for you -
all you need to do is handle receiving beacons and probe responses on
channels that aren't what you're currently on.  However the whole receive
path is peppered with ic->ic_curchan and manual scan/powersave handling.
The beacon parsing code also checks ic->ic_curchan to determine if the
received beacon is on the correct channel or not.[1]

So:

* add freq/ieee values to ieee80211_rx_stats;
* change ieee80211_parse_beacon() to accept the 'current' channel
  as an argument;
* modify the iv_input() and iv_recv_mgmt() methods to include the rx_stats;
* add a new method - ieee80211_lookup_channel_rxstats() - that looks up
  a channel based on the contents of ieee80211_rx_stats;
* if it exists, use it in the mgmt path to switch the current channel
  (which still defaults to ic->ic_curchan) over to something determined
  by rx_stats.

This is enough to kick-start scan offload support in the Intel 7260
driver that Rui/I are working on.  It also is a good start for scan
offload support for a handful of existing NICs (wpi, iwn, some USB
parts) and it'll very likely dramatically improve stability/performance
there.  It's not the whole thing - notably, we don't need to do powersave,
we should not scan all channels, and we should leave probe request sending
to the firmware and not do it ourselves.  But, this allows for continued
development on the above features whilst actually having a somewhat
working NIC.

TODO:

* Finish tidying up how the net80211 input path works.
  Right now ieee80211_input / ieee80211_input_all act as the top-level
  that everything feeds into; it should change so the MIMO input routines
  are those and the legacy routines are phased out.

* The band selection should be done by the driver, not by the net80211
  layer.

* ieee80211_lookup_channel_rxstats() only determines 11b or 11g channels
  for now - this is enough for scanning, but not 100% true in all cases.
  If we ever need to handle off-channel scan support for things like
  static-40MHz or static-80MHz, or turbo-G, or half/quarter rates,
  then we should extend this.

[1] This is a side effect of frequency-hopping and CCK modes - you
    can receive beacons when you think you're on a different channel.
    In particular, CCK (which is used by the low 11b rates, eg beacons!)
    is decodable from adjacent channels - just at a low SNR.
    FH is a side effect of having the hardware/firmware do the frequency
    hopping - it may pick up beacons transmitted from other FH networks
    that are in a different phase of hopping frequencies.
2015-05-25 16:37:41 +00:00
Gleb Smirnoff
c8550c0278 Make net80211 drivers supply their device name to the net80211 layer, so
that the latter doesn't need to go through struct ifnet to get their name.

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2015-05-25 13:51:13 +00:00
Jung-uk Kim
fd90e2ed54 CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten
years for head.  However, it is continuously misused as the mpsafe argument
for callout_init(9).  Deprecate the flag and clean up callout_init() calls
to make them more consistent.

Differential Revision:	https://reviews.freebsd.org/D2613
Reviewed by:	jhb
MFC after:	2 weeks
2015-05-22 17:05:21 +00:00
Adrian Chadd
03ab093569 Return the correct HAL data type for HAL_DIAG_ANI_STATS.
I .. stupidly added code to return HAL_ANI_STATS to HAL_DIAG_ANI_STATS.
I discovered this in a noisy environment when the returned values were
enough to .. well, make everything terrible.

So - restore functionality.

Tested:

* AR5416 (uses the AR5212 HAL), in a /very/ noisy 2GHz environment.
  Enough to trigger ANI to get upset and generate useful data.
2015-04-06 01:12:53 +00:00