Bug 167675 - The txmaxpow and txpower values I see from ifconfig(8) appear wrong.
Summary: The txmaxpow and txpower values I see from ifconfig(8) appear wrong.
Status: Open
Alias: None
Product: Base System
Classification: Unclassified
Component: wireless (show other bugs)
Version: Unspecified
Hardware: Any Any
: Normal Affects Only Me
Assignee: freebsd-wireless (Nobody)
Depends on:
Reported: 2012-05-07 12:40 UTC by Ryan
Modified: 2018-05-28 19:49 UTC (History)
0 users

See Also:


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Description Ryan 2012-05-07 12:40:11 UTC
I have a Compex WLM54G-26 wireless card (1)(2).  It uses an AR2413 chipset.  The following is partial output from "ifconfig".

regdomain FCC country CA indoor
txpowmax 50.0
txpower 30

The values given for "txpowmax" and "txpower" seem incorrect to me.  They do not appear to be using consistent units.  I'm making the assumption they should be showing dBm.  It's my understanding that net80211 stores these values as integers equal to 2xdBm, so it may be possible "txpowmax" is not being converted properly somewhere, but testing that assertion is beyond my ability at the moment.

Also, the WLM54G-26 is a 26dBm card.  Assuming "txpower" is displaying dBm, a value of "30" should not be possible.  If I change the regulatory domain, the value of "txpower" appears to be what I would expect.

regdomain 0 country US anywhere
txpowmax 50.0
txpower 26

However, both the CA and the US country codes fall under the "fcc" domain in "/etc/regdomain.xml", so I'm not sure why it has any impact.  Please note, I'm assuming "txpower" should match the output power of my card and I may be misunderstanding the values I should expect to see.

I originally started asking about this on the pfSense forums (3).  I also posted to the freebsd-wireless mailing list (4).

Also of note, I am not using a vanilla version of FreeBSD.  I am using pfSense 2.0.1 on an ALIX.2D13.


1: http://www.compex.com.sg/fullDescription.aspx?pID=28

2: http://www.compex.com.sg/Datasheets/WLM54G-26_DSv2.1.3.pdf

3: http://forum.pfsense.org/index.php/topic,48814.0.html

4: http://freebsd.1045724.n5.nabble.com/Where-can-I-find-information-about-the-txpower-and-txpowmax-values-from-ifconfig-td5689298.html

How-To-Repeat: Run "ifconfig -v ath0_wlan0".
Comment 1 Mark Linimon freebsd_committer freebsd_triage 2014-11-11 02:52:10 UTC
Comment 2 Eitan Adler freebsd_committer freebsd_triage 2018-05-28 19:49:51 UTC
batch change:

For bugs that match the following
-  Status Is In progress 
- Untouched since 2018-01-01.
- Affects Base System OR Documentation


Reset to open status.

I did a quick pass but if you are getting this email it might be worthwhile to double check to see if this bug ought to be closed.