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Ticket #837 (assigned defect)

Opened 15 years ago

Last modified 14 years ago

cannot set txpower > 17dbm

Reported by: bcrl@kvack.org Assigned to: mrenzmann (accepted)
Priority: major Milestone:
Component: madwifi: other Version: trunk
Keywords: Cc:
Patch is attached: 0 Pending:

Description (Last modified by mrenzmann)

Using imedia 2.7.4, it is impossible to set the transmit power within legal limits here in Canada for point to point links. This is with WLM54G23 cards

[root@imedia root]# iwconfig ath0 txpower 23
Error for wireless request "Set Tx Power" (8B26) :
    SET failed on device ath0 ; Invalid argument.
[root@imedia root]# iwconfig ath0 txpower 18
Error for wireless request "Set Tx Power" (8B26) :
    SET failed on device ath0 ; Invalid argument.
[root@imedia root]# iwconfig ath0 txpower 17
[root@imedia root]# 

Imedia is using svn1705 and reports the following at boot:

ath_hal: 0.9.17.2 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413, RF5413)
wlan: 0.8.4.2 (svn r1705)
ath_rate_sample: 1.2 (svn r1705)
wlan: mac acl policy registered
ath_pci: 0.9.4.5 (svn r1705)
wifi0: 11b rates: 1Mbps 2Mbps 5.5Mbps 11Mbps
wifi0: 11g rates: 1Mbps 2Mbps 5.5Mbps 11Mbps 6Mbps 9Mbps 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps
wifi0: H/W encryption support: WEP AES AES_CCM TKIP
wifi0: mac 7.8 phy 4.5 radio 5.6
wifi0: Use hw queue 1 for WME_AC_BE traffic
wifi0: Use hw queue 0 for WME_AC_BK traffic
wifi0: Use hw queue 2 for WME_AC_VI traffic
wifi0: Use hw queue 3 for WME_AC_VO traffic
wifi0: Use hw queue 8 for CAB traffic
wifi0: Use hw queue 9 for beacons
wifi0: Atheros 5212: mem=0x80000000, irq=12

Change History

08/24/06 08:52:55 changed by anonymous

check Ticket #826. It's about the same problem.

08/24/06 09:02:52 changed by mrenzmann

  • priority changed from critical to major.
  • version set to trunk.
  • description changed.

Please tell us the regdomain and countrycode that your card has set in its EEPROM (or, in case you changed the countrycode via the boot parameter countrycode, the value you used there).

08/24/06 15:35:33 changed by bcrl@kvack.org

This is with either the default (0) or Canada (124) set. In any event, the regulations here limit the EIRP, not the transmit power of the card. With a 23dbm txpower setting, I am well within the legal limits. Changing antennas to larger units is not an option given the location they are installed.

08/30/06 02:16:17 changed by bcrl@kvack.org

Testing with v0.9.2 shows the same results. One odd item is that occasionally an iwlist ath0 txpower in STA mode will include the 23dBm transmit power as an option, but it quickly reverts back to 17dBm.

ath_hal: 0.9.17.2 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413, RF5413)
wlan: 0.8.4.2 (0.9.2)
ath_rate_sample: 1.2 (0.9.2)
wlan: mac acl policy registered
ath_pci: 0.9.4.5 (0.9.2)
wifi0: 11b rates: 1Mbps 2Mbps 5.5Mbps 11Mbps
wifi0: 11g rates: 1Mbps 2Mbps 5.5Mbps 11Mbps 6Mbps 9Mbps 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps
wifi0: H/W encryption support: WEP AES AES_CCM TKIP
wifi0: mac 7.8 phy 4.5 radio 5.6
wifi0: Use hw queue 1 for WME_AC_BE traffic
wifi0: Use hw queue 0 for WME_AC_BK traffic
wifi0: Use hw queue 2 for WME_AC_VI traffic
wifi0: Use hw queue 3 for WME_AC_VO traffic
wifi0: Use hw queue 8 for CAB traffic
wifi0: Use hw queue 9 for beacons
wifi0: Atheros 5212: mem=0x80000000, irq=12
ath1: Added WDS MAC: 00:80:48:7e:16:ed

10/04/06 21:00:32 changed by bcrl@kvack.org

Is there any possible way to work around this? The 6dBm loss of power means that ACKs aren't able to get through and the link must be set to operate at 1Mbit as a result, despite the system being well below the EIRP limits here in Canada.

10/04/06 21:14:46 changed by mrenzmann

  • status changed from new to assigned.
  • owner set to mrenzmann.

Needs to be forwarded to Atheros/Sam for negotiation. Will try to take care of that next week.

11/22/06 17:36:46 changed by ahmet@thebluezone.com

We are seeing the same problem here. I have tested three high powered cards (26 dBm) but cannot exceed 21 dBm at antenna output. Also if I decrease power to a lower value then I can not reach the same old peak value afterwards although I increase the power to max. I have seen these on the spectrum analyzer.

12/10/06 13:43:05 changed by selelvian@myrealbox.com

In Australia, the limitation as set by ACMA is 4 watts (36dB) of EIRP. Using 26dB output with a 7.5dBi antenna does not exceed this limitation. So I'd really like to be able to set my transmit power to something more than the Intel card which I bought the card to replace.

The card is a mini-pci Senao NMP8602. It does not achieve 26db transmit power by fudging txpower rates (unlike the Ubiquity cards), and the limitation is quite bizarre, considering the Windows drivers actually allow 100mW (20dB) transmit power, and the madwifi drivers seem to be capped at 63mW (18dB).

Changing the country code to Australia doesn't seem to help. Regdomain 0.

The above is actually a repost of my post in ticket 826.

<rant> I'm actually quite irritated by the fact that they advertise a 26dB "long range" card, and then artificially cap it according to so-called legal regulations. Which they got wrong. This irks me. Because nowhere in the fine print do they state: "We will limit the transmit power on this card arbitrarily according to what we believe are the limits of transmission power in your country." </rant>

Sorry. I needed that. It's not personal, I'm just frustrated.

On a more positive note, is there any way to get around the (arbitrary) txpower limitation?

10/30/07 19:48:09 changed by bmeier

Hi

I have reported the same long time ago (May 2006) for country Argentina. This issue and the receiver sensity problem (I too have reported this a long time ago in the list (Sept. 2006)) from tiket #705 does prevent to use the nice madwifi driver with p2mp applications and really long distance links in the 802.11a band. Is there any chance we can expect that Sam or Atheros will take this issue some day? There has gone 1 1/2 year... I had to switch to 802.11b because I really don't want to use comercial products like mikrotik on which I cannot install what I want and StarOs? which has a leagal issue. But in 802.11b I have still mayor problems with noise because so much 802.11b networks ... And of course no comment about throughput in the 802.11b networks...

So my question is: What can we do to solve this issues?