Message-ID: <4FEC6447.7010007@cern.ch> (sfid-20120628_160402_161453_834B30B5)
Date: Thu, 28 Jun 2012 16:03:51 +0200
From: Jon Wikne <Jon.Wikne@cern.ch>
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To: Jon Wikne <Jon.Wikne@cern.ch>
CC: linux-wireless@vger.kernel.org,
	Mohammed Shafi <shafi.wireless@gmail.com>
Subject: Re: Mysterious hangs - cfg80211 - ath9k
References: <4FE03291.5030202@cern.ch> <CAD2nsn1U0UHjrDp7vh7rfvTP=BLB3FA+zLV9sgt1_T7gVvAYgg@mail.gmail.com> <4FE0CA6C.3080002@cern.ch>
In-Reply-To: <4FE0CA6C.3080002@cern.ch>
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Sender: linux-wireless-owner@vger.kernel.org

On 06/19/2012 08:52 PM, Jon Wikne wrote:
> On 06/19/2012 11:39 AM, Mohammed Shafi wrote:
>> On Tue, Jun 19, 2012 at 1:34 PM, Jon Wikne<Jon.Wikne@cern.ch> wrote:
>>> Hi List,
>>>
>>> I am experiencing a puzzling problem with WLAN on a Toshiba Qosmio
>>> F750 laptop, running CERN SLC 5.8 (mostly identical to RHEL 5.8),
>>> but with kernel 2.6.39.4. (The kernel that came with the distro did
>>> not work properly with WLAN on this machine at all.)
>>
>> please quickly try
>> http://linuxwireless.org/en/users/Download#Where_to_download_bleeding_edge
>
> I tried to install compat-wireless-2012-05-10. It worked for 4? hours,
> then same problem.
>
> Maybe there is something wrong with my understanding here, but I do not
> see why the "cfg80211: Calling CRDA to update world regulatory domain"
> should occur hours after the connection has been established, and what
> triggers it, apparently at random....
>
>> or the latest wireless testing tree
>> http://linuxwireless.org/en/developers/Documentation/git-guide#Cloning_latest_wireless-testing
>
> Is there a reason to believe it could make a difference if I try
> this too?

Now I downloaded this (more than 1GB), just to realize that it is a
complete kernel tree for kernel 3.5.0-rc3. I don't really feel ready
for an experimental upgrade from 2.6.39.4 to that right now....

With basis in compat-wireless-2012-05-10 I tried to comment out the
call to call_crda in net/wireless/reg.c and return -EALREADY in line
1483, just to see if that circumvented the problem. It did not. The
damage (whatever that might be) already seems to be done _before_ the
call_crda is made in reg.c.

I am a bit at a loss as to how to proceed. There are several things
i do not understand.

1) The call to update CRDA (even with my crude, experimental, dummy
return) seems to cause no trouble when it is done the first time
the line comes up. Could someone please explain to me what causes
the subsequent calls at highly irregular intervals, and why that
seems to be necessary or desirable?

2) Is this a known problem that is being worked on (in which case I
will just shut up and wait), or am I the first to report it?

Thanks in advance for any further info or suggestions.

Regards,
-- Jon Wikne