# [SOLVED]samsung series 7 laptop does not connect to 2.4Ghz

## devsk

When booted into Linux the driver iwlwifi is not able to connect to 2.4Ghz band of any router. The output from 'dmesg' shows it is timing out during authentication phase. The iwlist scan shows 70/70 signal strength and all parameters check out fine. But it just won't connect. There MAC filtering but the MAC of this laptop is allowed.

It connects fine to 5Ghz band on both the routers in the house.

If I boot into Windows 7, the same hardware connects to 2.4 Ghz band fine on both the routers. So, what gives? The card is Intel Centrino 6300 (the ultimate one).

This is a major headache because 5Ghz does not have a wide range (higher frequency signal dies shorter distances) and there are blind spots in my house where the laptop just can't connect to the network. I have to boot into Windows to be able to connect. This is unacceptable for a Linux geek... :Smile: 

Any ideas?

Edit: Finally, with kernel 3.10.7, I have a resolution to this issue. I can now connect to 2.4Ghz band as well. If you are wondering why I need 2.4Ghz while 5Ghz works, the reason is that 5Ghz is very lossy and range is small. So, I get 2.4Ghz signal better and more reliable at larger distances. I am a happy camper now.Last edited by devsk on Sun Aug 25, 2013 5:47 am; edited 1 time in total

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## cach0rr0

tried with 11n_disable=1 or 5ghz_disable=1 ?

shots in the dark. iwlwifi seems to be a very finicky beast. I have an iwl-1000 that just plain wont stay connected to the same AP (at home) my iwl-6005 stays connected to beautifully.

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## khayyam

devsk ...

You can disable 5GHz by disabling 802.11n ...

/etc/modprobe.d/iwlwifi.conf

```
options iwlwifi 11n_disable=1
```

I don't have an intel N card ... so thats the theory, never had to do it in practice.

best ... khay

EDIT: cach0rr0 beat me to it while I was chomping breakfast.Last edited by khayyam on Sun Mar 17, 2013 9:43 am; edited 1 time in total

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## devsk

Does anybody know what this message means? It seems to be precursor to all "timeouts" to authenticate.

```
wlan0: capabilities/regulatory prevented using AP HT/VHT configuration, downgraded
```

Looks like my laptop is being prohibited from accessing the AP while running Linux whereas it is allowed when running Windows.Last edited by devsk on Sun Mar 17, 2013 9:45 am; edited 1 time in total

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## devsk

I tried both those options in /etc/modprobe.d/iwlwifi.conf, did a reload of the iwlwifi module and it still does not allow me to connect.

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## khayyam

 *devsk wrote:*   

> Does anybody know what this message means? It seems to be precursor to all "timeouts" to authenticate. wlan0: capabilities/regulatory prevented using AP HT/VHT configuration, downgraded

 

devsk ... the 'regulatory domain' provides information on what capablities (channels, etc) are restricted for the domain.

You can try providing your regulatory domain to cfg80211 (assuming its a module)

/etc/modprobe.d/cfg80211.conf

```
options cfg80211 ieee80211_regdom=US
```

I'm not entirely sure this will work without net-wireless/wireless-regdb ... but you can try. Otherwise you can do the same with net-wireless/iw

```
#iw reg set US
```

See:  /usr/src/linux/Documentation/networking/regulatory.txt

best ... khayLast edited by khayyam on Sun Mar 17, 2013 9:52 am; edited 1 time in total

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## devsk

```
http://wireless.kernel.org/en/developers/Regulatory
```

What is this crap? Do we need to do something about this in Gentoo distro? Seems like kernel interacts with udev and some regulatory database in user space is being used to enforce the use of certain frequencies and channels. Why do these folks make life harder for us folks?... :Sad: 

Why would 2.4Ghz band be not allowed? And why only on Linux?

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## devsk

 *khayyam wrote:*   

>  *devsk wrote:*   Does anybody know what this message means? It seems to be precursor to all "timeouts" to authenticate. wlan0: capabilities/regulatory prevented using AP HT/VHT configuration, downgraded 
> 
> devsk ... the 'regulatory domain' provides information on what capablities (channels, etc) are restricted for the domain.
> 
> You can try providing your regulatory domain to cfg80211 (assuming its a module)
> ...

 net-wireless/wireless-regdb is there. But adding that option to the cfg80211 does not do anything. I will now try the iw utility.

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## khayyam

 *devsk wrote:*   

> 
> 
> ```
> http://wireless.kernel.org/en/developers/Regulatory
> ```
> ...

 

devsk ... its in the same realm as licences, gentoo can't do anything about the regulation set on radio frequency restrictions for certain juristictions.

 *devsk wrote:*   

> Seems like kernel interacts with udev and some regulatory database in user space is being used to enforce the use of certain frequencies and channels. Why do these folks make life harder for us folks?...

 

No, its not enforced ... you can set it to BO if you so choose, but note: setting the wrong regulatory domain could break the law in your country..

 *devsk wrote:*   

> Why would 2.4Ghz band be not allowed? And why only on Linux?

 

I'm not entirely sure this is your issue ...

best ... khay

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## devsk

Since that laptop is not on the net, I can't cut&paste. But here is the what appeared in the dmesg:

Hardware Name: 700Z7C

db.txt is empty, you should update it....

...backtrace here

And regulatory domain changed to US and one more frequency band got added. All frequencies between 2.4 and 5.2 Ghz are shown there.

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## khayyam

 *devsk wrote:*   

> 
> 
> ```
> wlan0: capabilities/regulatory prevented using AP HT/VHT configuration, downgraded
> ```
> ...

 

devsk ... looking at the above again, I think this is the result of disabling 802.11n ... I think HT is only available for N networks. So, I don't think its the cause of your authentication issue.

best ... khay

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## devsk

I still can't figure out why it works when booted in Windows.

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## ppurka

Are you using 3.8? I ran into the same problem after upgrading to 3.8. Currently I am on 3.8.2. I also found the following, and think it might be a related regression:

http://comments.gmane.org/gmane.linux.kernel.wireless.general/104268

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## devsk

That's much newer code than what's in 3.8.3 (I am on 3.8.3). So, the patch provided there won't even apply because the function being modified does not exist in 3.8.3 code.

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## ppurka

Hmm.. never mind. I found the bug corresponding to my wireless card.

http://www.spinics.net/lists/linux-wireless/msg104449.html

I am downgrading to 3.7. Enough with the "latest and greatest".   :Evil or Very Mad: 

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## devsk

It took 6 months, but the fix is here. Update to kernel 3.10.7 fixed the issue for me.

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