ath5k blind to nearby network

ath5k blind to nearby network

[Grzegorz Nowakowski]

Hello everyone,

I'm more or less ordinary Linux user: have used the system for a long
time.  While I'm accustomed to manual tweaking of the system, I gave up
regarding set up of secure wireless connection.  I rely on the tools,
networkmanager at the beginning, wicd now, to do the job.  Which was
performed rather well except lately, when I encounter strange problem.

The short version is: my laptop doesn't see my home network (and can't
connect to, too).

For longer one, there is needed some background.  The AP used is Motorola
WR850G running DD-WRT v24-sp1 (and v24-beta few months earlier).  The
laptop is Fujitsu-Siemens Lifebook E8310 with Atheros AR242x built in.
For reference, there is also another laptop, HP, with Intel IPW2200 on
board.  Both laptops run on Debian unstable with unpatched, custom configured
2.6.29.1 kernel.  What works or worked:

- HP
- FSC with Madwifi long time ago
- FSC running Windows XP
- FSC with Linux&ath5k few months ago

What doesn't:
- FSC with Linux&ath5k now
- FSC with Knoppix 6.1

The symptom is that with both NetworkManager and WICD (and "iwlist <if>
scanning") I don't see my home network on the list.  I see all other
neighbouring networks around and I'm even able to connect if any is
open.  Too much power on AP is not an issue as I lowered it to pathetic
level (30mW), besides HP doesn't complain.  Problem is probably not with
hardware nor with AP as WinXP on FSC connects flawlessly.

The only uncertainity is with the DD-WRT version as I'm not 100% sure if
the FSC worked after the firmware upgrade.  Most probably, yes.  Anyway,
WinXP still works.

I mentioned Madwifi only for completness.  I had bad experience with the
driver and I'm not going to use it unless I get really good argument
("it works for me" is not such one).

In summary, the problem seems to lie somewhere around ath5k driver on
this paritcular laptop connecting to this particular access point.  Now
I have no reason to believe there is an error in ath5k but I'm at loss
what to check more.  So maybe someone suggest what additional diagnosis
can I perform to better isolate the glitch?  Any suggestion is welcome.

As I don't subscribe to this list, please CC me when replying.

Thanks in advance and best regards,
-- 
Grzegorz Nowakowski

Re: ath5k blind to nearby network

[Tony Vroon]

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Re: ath5k blind to nearby network

[Grzegorz Nowakowski]

On Sat, Apr 11, 2009 at 05:19:55PM +0100, Tony Vroon wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> On Fri, 10 Apr 2009 23:39:58 +0200
> Grzegorz Nowakowski <krecik@hell.pl> wrote:
> > The symptom is that with both NetworkManager and WICD (and "iwlist
> > <if> scanning") I don't see my home network on the list.  I see all
> > other neighbouring networks around and I'm even able to connect if
> > any is open.
> 
> Please doublecheck your wireless regulatory setting. On the default
> "world" domain, it is unlikely you will be able to see networks on
> channel 13. You may well have chosen that specific channel because it
> was so quiet.

Gee, that was so stoopid!  You have guessed correctly, the channel in
use was indeed thirteenth and 13 was its number.  After reconfiguring
the AP to use another one everything seems to be working fine.

But that leaves me with the question: why Windows XP on Atheros and Linux
on Intel didn't have such trouble?

Anyway, thanks for suggestion and best regards.
-- 
Grzegorz Nowakowski

Re: ath5k blind to nearby network

[Gábor Stefanik]

On Mon, Apr 13, 2009 at 6:24 PM, Grzegorz Nowakowski <krecik@hell.pl> w=
rote:
> On Sat, Apr 11, 2009 at 05:19:55PM +0100, Tony Vroon wrote:
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>
>> On Fri, 10 Apr 2009 23:39:58 +0200
>> Grzegorz Nowakowski <krecik@hell.pl> wrote:
>> > The symptom is that with both NetworkManager and WICD (and "iwlist
>> > <if> scanning") I don't see my home network on the list. =A0I see =
all
>> > other neighbouring networks around and I'm even able to connect if
>> > any is open.
>>
>> Please doublecheck your wireless regulatory setting. On the default
>> "world" domain, it is unlikely you will be able to see networks on
>> channel 13. You may well have chosen that specific channel because i=
t
>> was so quiet.
>
> Gee, that was so stoopid! =A0You have guessed correctly, the channel =
in
> use was indeed thirteenth and 13 was its number. =A0After reconfiguri=
ng
> the AP to use another one everything seems to be working fine.
>
> But that leaves me with the question: why Windows XP on Atheros and L=
inux
> on Intel didn't have such trouble?

Windows XP auto-configures the regulatory domain based on your
regional settings. Intel cards have semi-hardcoded regulatory
information in their EEPROMs, which allows Linux to automatically
select the right regulatory settings. Atheros cards have no such
firmware-level regulatory enforcement.

>
> Anyway, thanks for suggestion and best regards.
> --
> Grzegorz Nowakowski
> --
> To unsubscribe from this list: send the line "unsubscribe linux-wirel=
ess" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at =A0http://vger.kernel.org/majordomo-info.html
>



--=20
Vista: [V]iruses, [I]ntruders, [S]pyware, [T]rojans and [A]dware. :-)
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Re: ath5k blind to nearby network

[Bob Copeland]

2009/4/13 G=E1bor Stefanik <netrolller.3d@gmail.com>:
> Windows XP auto-configures the regulatory domain based on your
> regional settings. Intel cards have semi-hardcoded regulatory
> information in their EEPROMs, which allows Linux to automatically
> select the right regulatory settings. Atheros cards have no such
> firmware-level regulatory enforcement.

=2E..yet.  Actually ath9k does, and there are patches for ath5k.

However, a lot of cards are programmed to be world roaming in the
eeprom too.  So 'iw reg set XX' is still your best bet.

--=20
Bob Copeland %% www.bobcopeland.com
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Re: ath5k blind to nearby network

[Luis R. Rodriguez]

2009/4/13 G=C3=A1bor Stefanik <netrolller.3d@gmail.com>:
> On Mon, Apr 13, 2009 at 6:24 PM, Grzegorz Nowakowski <krecik@hell.pl>=
 wrote:
>> On Sat, Apr 11, 2009 at 05:19:55PM +0100, Tony Vroon wrote:
>>> -----BEGIN PGP SIGNED MESSAGE-----
>>> Hash: SHA1
>>>
>>> On Fri, 10 Apr 2009 23:39:58 +0200
>>> Grzegorz Nowakowski <krecik@hell.pl> wrote:
>>> > The symptom is that with both NetworkManager and WICD (and "iwlis=
t
>>> > <if> scanning") I don't see my home network on the list. =C2=A0I =
see all
>>> > other neighbouring networks around and I'm even able to connect i=
f
>>> > any is open.
>>>
>>> Please doublecheck your wireless regulatory setting. On the default
>>> "world" domain, it is unlikely you will be able to see networks on
>>> channel 13. You may well have chosen that specific channel because =
it
>>> was so quiet.
>>
>> Gee, that was so stoopid! =C2=A0You have guessed correctly, the chan=
nel in
>> use was indeed thirteenth and 13 was its number. =C2=A0After reconfi=
guring
>> the AP to use another one everything seems to be working fine.
>>
>> But that leaves me with the question: why Windows XP on Atheros and =
Linux
>> on Intel didn't have such trouble?
>
> Windows XP auto-configures the regulatory domain based on your
> regional settings.

Not quite.

>  Intel cards have semi-hardcoded regulatory
> information in their EEPROMs, which allows Linux to automatically
> select the right regulatory settings.

Sort of right.

> Atheros cards have no such
> firmware-level regulatory enforcement.

Wrong.

The right answer is the windows Atheros driver uses the EEPROM for
regulatory enforcement. The Intel drivers, depending on the card
through different regulatory domain SKUs, also use their EEPROM
information for regulatory compliance but are mostly always configured
to a sort of world roaming regulatory domain. Both the Intel windows
and Linux drivers make use of these regulatory domains.

The reason why you may not see Channel 13 on ath5k is the old ath5k
doesn't make use of the EEPROM to take advantage of setting your
regulatory environment.

As Bob indicated though and mainly thanks to his efforts, ath5k will
soon be doing this so you won't have to be specifying your regulatory
domain manually.

  Luis
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