[ath9k-devel] ath9k WPA2-PEAP MSCHAPV2 Connectivity issue

[Ben Greear <greearb@candelatech.com>]

On 10/28/2013 07:34 AM, ???????? ????????? wrote:
> On 2013-09-19 17:01, James Hogan:
>> I think I have stumbled on to the real issue. I'm sorry if I have been
>> wasting your time at all. Apparently, the network is having problems
>> with all wireless-n mode cards.
>> The network doesn't like how wireless-n is roaming to the different AP's
>> and is registering as me disconnecting when the wireless card tries to
>> connect to roam to the other AP.
>> It's not just ath9k though, Ra-Link and other cards are having these
>> issues as well. Is there a way to disable or to make it possible to
>> disable the wireless-n mode of the card and just
>> use wireless abg? On a note, I noticed when I passed to the command line
>> "iw event -r" that at about the time my card would scan, that is when I
>> would stop receiving service even though
>> my cards never registered as being disconnected. After the scan, the
>> card just continues to reissue scans. Sometimes however, it will try to
>> reconnect me to the network.  I was talking to one of the IT employees
>> in my class today and he said that they have been having this issue with
>> all of the newer higher-end cards.
> 
> I've been having a similar problem, potentially the same.  My
> university updated the firmware in their access points in August, and
> while I can still associate with the APs with no trouble, I can only
> get traffic through for short periods of time.  As in James's case, I
> seem to lose service around when my card scans.
> 
> I have been told by my university's wireless team that they are aware
> that this issue affects most linux users on campus, but don't
> currently have any solution.  Their suggested work-around is to
> disable 11n speeds, which apparently "solves" the problem for most
> users.  However, while iwconfig can be used to set various rates when
> connected to my 11g router at home, the speed seems to be locked at
> 65Mbps when I'm associated with the router on campus.  That is, "sudo
> iwconfig wlan0 rate 54M" and similar directives seem to have no
> effect.
> 
> For reference, I have an AR9285 card and so far have been using the
> ath9k driver that comes with my 3.2.0 debian stock kernel (which might
> technically be 3.2.41?).  I have noticed nothing unusual about using
> any other networks, including 11n ones elsewhere.
> 
> On 2013-09-21 05:40, Ben Greear wrote:
>> If you are using ath9k rate control, please try disabling that and use
> the minstrel-ht rate control instead.
>>
>> With a modern wpa_supplicant and kernel you can just disable HT in
> the supplicant config, by the way.
>>
>>
>> # disable_ht: Whether HT (802.11n) should be disabled.
>> # 0 = HT enabled (if AP supports it)
>> # 1 = HT disabled
>> #
>> # disable_ht40: Whether HT-40 (802.11n) should be disabled.
>> # 0 = HT-40 enabled (if AP supports it)
>> # 1 = HT-40 disabled
> 
> I found I had an older version of wpa_supplicant (v1.0, which is what
> appears to be current in debian unstable) that did not support
> disable_ht and disable_ht40, so I downloaded a newer version (v2.0)
> and compiled it with CONFIG_HT_OVERRIDES enabled.  Using that, I was
> able to add disable_ht=1 and disable_ht40=1 to the network block of my
> wpa_supplicant configuration file.
> 
> When I run wpa_supplicant now in debug mode, it seems to parse these
> directives, and even outputs lines like "wlan0: set_disable_ht40: 1"
> where it seems to be telling the driver to disable the mode.  However,
> iwconfig still indicates that the speed is 65Mbps, and no number of
> times manually telling it otherwise seems to have any impact on it.
> 
> I don't know whether this limitation is due to an issue with the ath9k
> driver, with wpa_supplicant, or with something else, or is simply my
> misperception of how things should work.  Either way, I'm tempted to
> apply the patch to my ath9k source that James posted so that I can
> disable 11n modes altogether, but I'm more than willing to try other
> suggestions.

I think your kernel is too old to support that feature, it is relatively
recent.

And, while I know it works with ath9k, I'm not sure it works with other
drivers.

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com