When beacons get stuck in AP mode, the most likely cause is interference.
Such interference can often go on for a while, and too many consecutive
beacon misses can lead to connected clients getting dropped.
Since connected clients might not be subjected to the same interference
if that happens to be very local, the AP should try to deal with it as
good as it can. One way to do this is to trigger an NF calibration with
automatic baseband update right after the beacon miss. In my tests with
very strong interference, this allowed the AP to continue transmitting
beacons after only 2-3 misses, which allows a normal client to stay
connected.
With some of the newer - really sensitive - chips, the maximum noise
floor limit is very low, which can be problematic during very strong
interference. To avoid an endless loop of stuck beacons -> nfcal ->
periodic calibration -> stuck beacons, the beacon miss event also sets
a flag, which allows the calibration code to bypass the chip specific
maximum NF value. This flag is automatically cleared, as soon as the
first NF median goes back below the limits for all chains.
In my tests, this allowed an ath9k AP to survive very strong interference
(measured NF: -68, or sometimes even higher) without losing connectivity
to its clients. Even under these conditions, I was able to transmit
several mbits/s through the interface.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
On AR5008-AR9002, other forms of calibration must not be started while
the noise floor calibration is running, as this can create invalid
readings which were sometimes not even recoverable by any further
calibration attempts.
This patch also ensures that the result of noise floor measurements
are processed faster and also allows the result of the initial
calibration on reset to make it into the NF history buffer
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The noise floor history buffer is currently not kept per channel, which
can lead to problems when changing channels from a clean channel to a
noisy one. Also when switching from HT20 to HT40, the noise floor
history buffer is full of measurements, but none of them contain data
for the extension channel, which it needs quite a bit of time to recover
from.
This patch puts all the per-channel calibration data into a single data
structure, and gives the the driver control over whether that is used
per-channel or even not used for some channels.
For ath9k_htc, I decided to keep this per-channel in order to avoid
creating regressions.
For ath9k, the data is kept only for the operating channel, which saves
some space. ath9k_hw takes care of wiping old data when the operating
channel or its channel flags change.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
On AR9003 the initial noise floor calibration is currently triggered
at the end of the reset without allowing the hardware to update the
baseband settings. This could potentially make scans in noisy
environments a bit more unreliable, so use the same calibration
sequence that is used on AR9002.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Acked-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
AR5008+ and AR9003 currently use two separate implementations of the
ath9k_hw_loadnf function. There are three main differences:
- PHY registers for AR9003 are different
- AR9003 always uses 3 chains, earlier versions are more selective
- The AR9003 variant contains a fix for NF load timeouts
This patch merges the two implementations into one, storing the
register array in the ath_hw struct. The fix for NF load timeouts is
not just relevant for AR9003, but also important for earlier hardware,
so it's better to just keep one common implementation.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This refactors the noise floor range checks to make them generic,
and adds proper ranges for each supported chip type.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This is the last call on calib.c which acceses PHY stuff,
with this change we calib.c is now generic between both
all supported hardware families.
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Calibration code touches phy registers and since these
change the calibration code needs to be abstracted.
Noise floor calibration is the only thing remaining but
since the remaining calls only touch the AR_PHY_AGC_CONTROL
register we'll just define that register conditionally, that
will be done separately. The goal is to remove the dependency
of ar9002_phy.h on calib.c
This also adds stubs to be filled for AR9003 calibration code.
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
ath9k uses this for now, ath9k_htc is expected to re-use this
as well. We lave ath5k as is, but it certainly can also be
converted later.
The ath9k module parameter and debugfs entry is kept.
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The default noise floor was never initialized for
AR9287.This patch helps in reporting the correct
RSSI for this version of chipset.
Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
PA calibration need not be done if the offset is not varying.
The current logic does PA calibration even if the offset is the
same.
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
RSSI reported by the RX descriptor requires little manipulation.
Manipulate and report the correct RSSI to the stack. This will
fix the improper signal levels reported by iwconfig iw dev wlanX
station dump. Also the Link Quality reported seems to be varying
(falls to zero also sometimes) when iperf is run from STA to AP.
Also use the default noise floor for now as the one reported
during the caliberation seems to be wrong.
The Signal and Link Quality before this patch (taken while TX is
in progress from STA to AP)
09:59:13.285428037 Link Quality=29/70 Signal level=-81 dBm
09:59:13.410660084 Link Quality=20/70 Signal level=-90 dBm
09:59:13.586864392 Link Quality=21/70 Signal level=-89 dBm
09:59:13.710296281 Link Quality=21/70 Signal level=-89 dBm
09:59:13.821683064 Link Quality=25/70 Signal level=-85 dBm
09:59:13.933402989 Link Quality=24/70 Signal level=-86 dBm
09:59:14.045839276 Link Quality=26/70 Signal level=-84 dBm
09:59:14.193926673 Link Quality=23/70 Signal level=-87 dBm
09:59:14.306230262 Link Quality=31/70 Signal level=-79 dBm
09:59:14.419459667 Link Quality=26/70 Signal level=-84 dBm
09:59:14.530711167 Link Quality=37/70 Signal level=-73 dBm
09:59:14.642593962 Link Quality=29/70 Signal level=-81 dBm
09:59:14.754361169 Link Quality=21/70 Signal level=-89 dBm
09:59:14.866217355 Link Quality=21/70 Signal level=-89 dBm
09:59:14.976963623 Link Quality=28/70 Signal level=-82 dBm
09:59:15.089149809 Link Quality=26/70 Signal level=-84 dBm
09:59:15.205039887 Link Quality=27/70 Signal level=-83 dBm
09:59:15.316368003 Link Quality=23/70 Signal level=-87 dBm
09:59:15.427684036 Link Quality=36/70 Signal level=-74 dBm
09:59:15.539756380 Link Quality=21/70 Signal level=-89 dBm
09:59:15.650549093 Link Quality=22/70 Signal level=-88 dBm
09:59:15.761171672 Link Quality=32/70 Signal level=-78 dBm
09:59:15.872793750 Link Quality=23/70 Signal level=-87 dBm
09:59:15.984421694 Link Quality=22/70 Signal level=-88 dBm
09:59:16.097315093 Link Quality=21/70 Signal level=-89 dBm
The link quality and signal level after this patch (take while
TX is in progress from STA to AP)
17:21:25.627848091 Link Quality=65/70 Signal level=-45 dBm
17:21:25.762805607 Link Quality=65/70 Signal level=-45 dBm
17:21:25.875521888 Link Quality=66/70 Signal level=-44 dBm
17:21:25.987468448 Link Quality=66/70 Signal level=-44 dBm
17:21:26.100628151 Link Quality=66/70 Signal level=-44 dBm
17:21:26.213129671 Link Quality=66/70 Signal level=-44 dBm
17:21:26.324923070 Link Quality=65/70 Signal level=-45 dBm
17:21:26.436831357 Link Quality=65/70 Signal level=-45 dBm
17:21:26.610356973 Link Quality=65/70 Signal level=-45 dBm
17:21:26.723340047 Link Quality=65/70 Signal level=-45 dBm
17:21:26.835715293 Link Quality=64/70 Signal level=-46 dBm
17:21:26.949542748 Link Quality=64/70 Signal level=-46 dBm
17:21:27.062261613 Link Quality=65/70 Signal level=-45 dBm
17:21:27.174511563 Link Quality=64/70 Signal level=-46 dBm
17:21:27.287616232 Link Quality=64/70 Signal level=-46 dBm
17:21:27.400598119 Link Quality=64/70 Signal level=-46 dBm
17:21:27.511381404 Link Quality=64/70 Signal level=-46 dBm
17:21:27.624530421 Link Quality=65/70 Signal level=-45 dBm
17:21:27.737807109 Link Quality=64/70 Signal level=-46 dBm
17:21:27.850861352 Link Quality=65/70 Signal level=-45 dBm
17:21:27.963369436 Link Quality=64/70 Signal level=-46 dBm
17:21:28.076582289 Link Quality=64/70 Signal level=-46 dBm
Signed-off-by: Senthil Balasubramanian <senthilkumar@atheros.com>
Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch replaces old 'hal_' prefixes with 'ath9k_'.
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch cleans up the functions dealing with calibration,
using proper return values.
ath9k_hw_per_calibration(), ath9k_hw_calibrate now return bool values
instead of setting error values in the function arguments.
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Felix Fietkau