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Ticket #2336 (new defect)

Opened 13 years ago

Last modified 11 years ago

Madwifi driver + AR2413 chipset transmitting higher power at lower band(<2.4012 Ghz) when there are no AP

Reported by: Assigned to:
Priority: blocker Milestone:
Component: madwifi: driver Version: trunk
Keywords: Cc:
Patch is attached: 0 Pending: 0


I am having the issue Madwifi driver + AR2413 chipset transmitting higher power at lower band(<2.4012 Ghz) when there are no AP. Verified this by connecting spectrum analyzer and seeing the transmitted power.

I am using the chipset AR2413 and madwifi driver svn revision 4022. More details of

lspci 03:0f.0 Ethernet controller: Atheros Communications, Inc. AR5005G 802.11abg NIC (rev 01)

Subsystem: Atheros Communications, Inc. Compex Wireless 802.11 b/g MiniPCI Adapter, Rev A1 [WLM54G] Flags: bus master, medium devsel, latency 96, IRQ 20 Memory at dfce0000 (32-bit, non-prefetchable) [size=64K] Capabilities: [44] Power Management version 4

dmesg when the module is loaded MadWifi: ath_attach: Switching rfkill capability off. wifi0: Atheros AR2413 chip found (MAC 7.8, PHY 2112A 4.5, Radio 5.6) ath_pci: wifi0: Atheros 2413: mem=0xdfce0000, irq=20

I am using wpa_supplicant, the wpa_supplicant.conf settings are ctrl_interface=/var/run ctrl_interface_group=<groupname> update_config=1

Since this is operated in germany, I am setting the regdomain to 0x37 in EEPROM of chip using ath_info utility ath_info -f -w dfce0000 regdomain=0x37

Then loading the driver using countrycode settings modprobe ath_pci countrycode=276

strating the wpa_supplicant

Note there are on access point available and when we measure the transmit power it shows 10dbm higher in lower band(<channel1(2.4012Ghz), this is violating the german ETSI regulations . As soon as access point/ssid becomes available the power level goes down and is within germany regulation.

When does the maxtxpower gets set ? I am not sure if the driver is initializing all the values when I load the madwifi driver with germany country-code or it does later when it find a AP during scan. Any solution to this would help greatly, this blocking from product being passed for certification.

Graph1 shows the violation that is shaded part. Graph 2 shows both when AP was not available and when AP was available.


graph.tar.gz (49.9 kB) - added by on 08/13/09 19:38:57.

Change History

08/13/09 19:38:57 changed by

  • attachment graph.tar.gz added.


08/13/09 20:13:10 changed by

I am using Madwifi trunk-r4022 and linux version

output of iwconfig ~ # iwconfig lo no wireless extensions.

eth0 no wireless extensions.

wifi0 no wireless extensions.

Warning: Driver for device ath0 has been compiled with version 22 of Wireless Extension, while this program supports up to version 20. Some things may be broken...

ath0 IEEE 802.11g ESSID:"" Nickname:""

Mode:Managed Frequency:2.437 GHz Access Point: Not-Associated Bit Rate:0 kb/s Tx-Power:16 dBm Sensitivity=1/1 Retry:off RTS thr:off Fragment thr:off Encryption key:off Power Management:off Link Quality=0/70 Signal level=-96 dBm Noise level=-96 dBm Rx invalid nwid:37850 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0