[ath9k-devel] Could not set tx-power over 15 dBM

[Angel Arancibia]

Hi,

I got a Atheros AR9285 that i can't increase tx-power level over 15 dBM.
The problem is that at such power, the connection is (very) unstable when
i'm not near the AP.

when I try to increae tx-power

[***@Gauchita etc]# iwconfig wlan0 txpower 16dBM
Error for wireless request "Set Tx Power" (8B26) :
SET failed on device wlan0 ; Invalid argument.


[***@Gauchita etc]# iw reg get
country BO:
(2402 - 2482 @ 40), (N/A, 30)
(5735 - 5835 @ 40), (N/A, 30)


More info about environment: (using compat-wireless 3.4-rc3-1 )

[***@Gauchita etc]# uname -a
Linux Gauchita 3.2-CHAKRA #1 SMP PREEMPT Tue Feb 28 14:55:18 UTC 2012
x86_64 Intel(R) Core(TM) i3-2330M CPU @ 2.20GHz GenuineIntel GNU/Linux

[***@Gauchita etc]# hwinfo --wlan
13: PCI 200.0: 0282 WLAN controller
[Created at pci.319]
Unique ID: y9sn.apYiokQ9666
Parent ID: qTvu.lbqpt3ZK2l3
SysFS ID: /devices/pci0000:00/0000:00:1c.1/0000:02:00.0
SysFS BusID: 0000:02:00.0
Hardware Class: network
Model: "Atheros AR9285 Wireless Network Adapter (PCI-Express)"
Vendor: pci 0x168c "Atheros Communications Inc."
Device: pci 0x002b "AR9285 Wireless Network Adapter (PCI-Express)"
SubVendor: pci 0x1a3b
SubDevice: pci 0x1089
Revision: 0x01
Driver: "ath9k"
Driver Modules: "ath9k", "ath9k"
Device File: wlan0
Features: WLAN
Memory Range: 0xd0500000-0xd050ffff (rw,non-prefetchable)
IRQ: 17 (no events)
HW Address: 74:2f:68:01:c2:31
Link detected: yes
WLAN channels: 1 2 3 4 5 6 7 8 9 10 11 12 13 14
WLAN frequencies: 2.412 2.417 2.422 2.427 2.432 2.437 2.442 2.447 2.452
2.457 2.462 2.467 2.472 2.484
WLAN encryption modes: WEP40 WEP104 TKIP CCMP
WLAN authentication modes: open sharedkey wpa-psk wpa-eap
Module Alias: "pci:v0000168Cd0000002Bsv00001A3Bsd00001089bc02sc80i00"
Driver Info #0:
Driver Status: ath9k is active
Driver Activation Cmd: "modprobe ath9k"
Config Status: cfg=new, avail=yes, need=no, active=unknown
Attached to: #7 (PCI bridge)


[***@Gauchita etc]# modinfo ath9k
filename:
/lib/modules/3.2-CHAKRA/updates/drivers/net/wireless/ath/ath9k/ath9k.ko
license: Dual BSD/GPL
description: Support for Atheros 802.11n wireless LAN cards.
author: Atheros Communications
alias: platform:ar934x_wmac
alias: platform:ar933x_wmac
alias: platform:ath9k
alias: pci:v0000168Cd00000034sv*sd*bc*sc*i*
alias: pci:v0000168Cd00000033sv*sd*bc*sc*i*
alias: pci:v0000168Cd00000032sv*sd*bc*sc*i*
alias: pci:v0000168Cd00000030sv*sd*bc*sc*i*
alias: pci:v0000168Cd0000002Esv*sd*bc*sc*i*
alias: pci:v0000168Cd0000002Dsv*sd*bc*sc*i*
alias: pci:v0000168Cd0000002Csv*sd*bc*sc*i*
alias: pci:v0000168Cd0000002Bsv*sd*bc*sc*i*
alias: pci:v0000168Cd0000002Asv*sd*bc*sc*i*
alias: pci:v0000168Cd00000029sv*sd*bc*sc*i*
alias: pci:v0000168Cd00000027sv*sd*bc*sc*i*
alias: pci:v0000168Cd00000024sv*sd*bc*sc*i*
alias: pci:v0000168Cd00000023sv*sd*bc*sc*i*
depends: ath9k_hw,ath9k_common,mac80211,ath,cfg80211,compat
vermagic: 3.2-CHAKRA SMP preempt mod_unload modversions
parm: debug:Debugging mask (uint)
parm: nohwcrypt:Disable hardware encryption (int)
parm: blink:Enable LED blink on activity (int)
parm: btcoex_enable:Enable wifi-BT coexistence (int)


If you need any other info, please let me know.

Thanks,

[Holger Schurig]

Why do you use "iw" to display your regulatory domain, but then the
antique "iwconfig" to set it? "iwconfig" can be deleted from any
moder system, it's outdated and virtually unsupported now.

Do "iw | grep txpower" to see the tx power related capabilities of iw.
If you then get an error, you'll much more likely getting an answer
here.

That said, a quick test of this didn't work for me: "iw wlan0 set
txpower limit 10" or "set txpower fixed 15" and so on always gave me
error -95: Operation not supported.

[Angel Arancibia]

Post by Holger Schurig
Why do you use "iw" to display your regulatory domain, but then the
antique "iwconfig" to set it? "iwconfig" can be deleted from any
moder system, it's outdated and virtually unsupported now.
Do "iw | grep txpower" to see the tx power related capabilities of iw.
If you then get an error, you'll much more likely getting an answer
here.
That said, a quick test of this didn't work for me: "iw wlan0 set
txpower limit 10" or "set txpower fixed 15" and so on always gave me
error -95: Operation not supported.

First of all, thanks for your answer and time.

In second place, i've also try using iw to set tx-power over 15dBM, but
whith the same result. The problem was that the reg domain in the EEPROM
has that restriction.

I could finally set grater power level changing the EEPROM reg domain to AR
(i'm from Argentina). As far I know ath9k does not support EEPROM writing
(in contrast to ath5k, doesn't it?) so I have done it as suggested in
dd-wrt forum [1]. After that, i could set using iwconfig and/or iw.

Anyway, the original problem that i was trying to fix was [2] the horrible
performance of my AR9285 (if i'm more than 5m .. 10m from the AP, the
connection goes down, when others laptops got 40% signal quality), and
increasing the tx-power has practicaly no efect on it.

As I has mentioned in [3], it seems not to be a specific issue of ath9k
(also happend in windows7 whit the last driver) but a hardware problem.
The connection goes down whit link Quality=33/70 Signal level=-77 dBm.

Of corse, i'm not sure :) . if Anyone has any suggestion or any help will
be apreciated.



[1]: *http://www.dd-wrt.com/phpBB2/viewtopic.php?p=491145#491145*
[2]: http://chakra-project.org/bbs/viewtopic.php?pid=53615#p53615
[3]: *http://chakra-project.org/bbs/viewtopic.php?pid=53713#p53713*

[Holger Schurig]

Maybe you have some similar problem as I, e.g. either an antenna
diversity problem and/or an ANI problem.

If your WLAN device has several antennas and the wrong input is
selected, then the driver is deaf. Moving away this little from the AP
might get you disconnected then.

If your WLAN device detects too much noise (or the noise detection is
buggy), then ANI (adaptive noise immunity) attenuates the incoming
signal. Again you get a bit deaf. But this time by purpose, so that
the reception part of the WLAN chip doesn't get overdriven and into
clipping mode. ANI can be disabled, one of the ath9k-modules (afaik
ath9k_hw) has a disable_ani= command line parameter.

Also, you can turn on ANI debugging to get a bit of output from ANI
with specifing debug=0x40 to the ath9k.ko module.


Note that increasing your own txpower doesn't help against a deaf reception.

[Angel Arancibia]

Hi,

Thanks again for your time

2012/5/14 Holger Schurig

Post by Holger Schurig
Maybe you have some similar problem as I, e.g. either an antenna
diversity problem and/or an ANI problem.
If your WLAN device has several antennas and the wrong input is
selected, then the driver is deaf. Moving away this little from the AP
might get you disconnected then.

There is any way to check this? At least, what is the input selected? I
think an antena issue is the most probable reason.

Post by Holger Schurig
If your WLAN device detects too much noise (or the noise detection is
buggy), then ANI (adaptive noise immunity) attenuates the incoming
signal. Again you get a bit deaf. But this time by purpose, so that
the reception part of the WLAN chip doesn't get overdriven and into
clipping mode. ANI can be disabled, one of the ath9k-modules (afaik
ath9k_hw) has a disable_ani= command line parameter.

I've got something wrong here ...

$ modprobe -r ath9k
$ modprobe -i ath9k_hw disable_ani=1
ERROR: could not insert 'ath9k_hw': No such file or directory
(dmesg) : ath9k_hw: Unknown parameter `disable_ani'


I can see a ath9k_hw parameter 'force_new_ani' set to 0, but i don't know
if it reffers to the same.

$ cat /sys/module/ath9k_hw/parameters/force_new_ani
0


Also, you can turn on ANI debugging to get a bit of output from ANI

Post by Holger Schurig
with specifing debug=0x40 to the ath9k.ko module.

$ modprobe -i ath9k debug=0x40

but ...

$ ls -l /sys/kernel/debug/ieee80211/phy0/
total 0

Where I should look for ANI debug messages?

Post by Holger Schurig
Note that increasing your own txpower doesn't help against a deaf reception.

:)

Thanks,
Angel

[Holger Schurig]

Post by Angel Arancibia
Where I should look for ANI debug messages?

dmesg !


And the disable_ani thingy is in the procfc, not a command line parameter:

echo 1 >/sys/kernel/debug/ieee80211/phy0/ath9k/disable_ani

[Angel Arancibia]

Post by Holger Schurig

Post by Angel Arancibia
Where I should look for ANI debug messages?

dmesg !
echo 1 >/sys/kernel/debug/ieee80211/phy0/ath9k/disable_ani

Thats the problem, i don't have the
'/sys/kernel/debug/ieee80211/phy0/ath9k/disable_ani' file neither
'/sys/kernel/debug/ieee80211/phy0/ath9k' dir.

/sys/kernel/debug/ieee80211/phy0/ is empty

[***@Gauchita ~]# ls -l /sys/kernel/debug/ieee80211/phy0/
total 0


I need to do something to get that file created?

Thanks,

[Holger Schurig]

Hmm, define CONFIG_CFG80211_DEBUGFS, CONFIG_MAC80211_DEBUGFS and
CONFIG_ATH9K_DEBUGFS and recompile?

And maybe you also need to mount /sys/kernel/debugfs in the first
place? Is that directory empty or not?

What's the contents of /sys/kernel/debug/ieee80211 ? Maybe it's not
phy0, but phy1 or even higher? Each reloading increases the phy
number, strangely enought.

[Angel Arancibia]

Post by Holger Schurig
Hmm, define CONFIG_CFG80211_DEBUGFS, CONFIG_MAC80211_DEBUGFS and
CONFIG_ATH9K_DEBUGFS and recompile?

I will check that.

Post by Holger Schurig
And maybe you also need to mount /sys/kernel/debugfs in the first
place? Is that directory empty or not?
What's the contents of /sys/kernel/debug/ieee80211 ? Maybe it's not
phy0, but phy1 or even higher? Each reloading increases the phy
number, strangely enought.

yep, debugfs is up and running :) . inside /sys/kernel/debug/ieee80211
there is only phy0, but phy0 is empty.

I will check the constant setting when i get back to home.

Thanks

[Angel Arancibia]

Post by Angel Arancibia

Post by Holger Schurig
Hmm, define CONFIG_CFG80211_DEBUGFS, CONFIG_MAC80211_DEBUGFS and
CONFIG_ATH9K_DEBUGFS and recompile?

I will check that.

seems that they were enable last time i've compiled compat-wireless.

[***@Gauchita compat-wireless-3.4-rc3-1]$ grep -r
CONFIG_CFG80211_DEBUGFS .
./config.mk:# CONFIG_CFG80211_DEBUGFS=y
./defconfigs/atheros-debug.mk:CONFIG_CFG80211_DEBUGFS=y
./patches/99-change-makefiles.patch: cfg80211-$(CONFIG_CFG80211_DEBUGFS) +=
debugfs.o

[***@Gauchita compat-wireless-3.4-rc3-1]$ grep -r
CONFIG_MAC80211_DEBUGFS .
./config.mk:# CONFIG_MAC80211_DEBUGFS=y
./defconfigs/atheros-debug.mk:CONFIG_MAC80211_DEBUGFS=y

[***@Gauchita compat-wireless-3.4-rc3-1]$ grep -r CONFIG_ATH9K_DEBUGFS
.
./config.mk:# CONFIG_ATH9K_DEBUGFS=y
./defconfigs/atheros-debug.mk:CONFIG_ATH9K_DEBUGFS=y





[***@Gauchita ~]# ls -l /sys/kernel/debug/ieee80211/
total 0
drwxr-xr-x 2 root root 0 16.05.2012 07:07 phy0/
[***@Gauchita ~]# ls -l /sys/kernel/debug/ieee80211/phy0/
total 0